Pros: First of all, I religiously look at reviews for products like this, as for many it is a big purchase and there are a lot of choices (brix, nuc, etc.) so I feel very inclined to write one myself. I am writing this review past the hype or dumb (in my opinion) reasons for the one star reviews.

Below I try and simplify and then summarize for the different types of users.I would love to give this unit 5 stars, because I feel users are way too picky and expect perfection. I originally was going to replace my Acer Aspire with i3-4160, 8GB DDR3, Crucial SSD, and GT730 1GB DDR5, but decided to go back to this computer instead of the NUC, but see why below why I still rate it high.

Pro's: (Perfect for: Mid-Range Business Users, Basic Users on Internet, Facebook, etc. Or for Video Encoding, Spreadsheets, etc).
-Awesome Visual BIOS!
-Very small (looks smaller than imaged!)
-Very Fast and efficient processor (i5-5250u w/HD 6000 graphics)
-Even if you are computer illiterate, putting together is so easy to do.
-With 16 GB Kingston HyperX RAM and 850 SSD Samsung EVO it flies.
-Very small footprint and will save some electricity costs (only around 15w this eats up)
-4 USB 3.0 ports and ethernet port make it very versatile and easy to connect devices.
-Very quiet IF (SEE BELOW) you don't do any gaming & change the fan to 27% instead of 40% in BIOS

Cons: Con's: (Horrible for: Entry-Mid Level Gaming (I occasionally play games maybe twice a week)
-Intel should not market this as a "LAN PARTY" device. I know it is not suppose to play modern gaemes, but I have mid-level games and I could not bear the sound, see the next point.
-Under gaming loads, this is HOT & LOUD! The HD Graphics 6000 are very admirable and do a good job; however in my opinion the noise is unbearable. In the BIOS i messed with the system fans, and felt the best minimum fan temp (with the processor idle at 50C, was to set it at 27% compared to the 40% that is standard (puts the idle at 40C). You cannot hear it at this sound, and doing "desktop work" like internet facebook netflix, etc. However when gaming, this thing sounds like a jet engine when you modify game graphic settings to look the best for the performance: around 30FPS. I tried modifying the fan settings to a desirable level at say a laptop may get at (while at 30FPS), and I found that this speed the CPU approached 90C, dangerous for this. Even at this fan level (around 4500RPM-5000) it was extremely bothersome, even when putting this under my desk. Understandingly, the fan goes into "emergency mode" and fired it at 100% fan speed.
-Mini HDMI port is very annoying if trying to make it portable, yet not intolerable.

Other Thoughts: To conclude, this unit I am keeping for any clients who need a very powerful workstation, or any other users who do not do anything except VERY LIGHT gaming. This unit gets way too hot for even older games (AOE III, AOM, Sims 3, Rome Total War). Now I am not a gamer, but I do occasionally enjoy PC games. With this unit I was so annoyed I stopped playing it. I loved the small factor, and ability to play games, but there is NOT silent operation at games whatsoever, I did not expect silent, but I expected a typical laptop fan speed.

I wrote this to try and help others who may be in my spot (mid-power user who occasionally plays 5-10 year old games). Keep this for strict Home Entertainment use or for Workstations. Kind of upset at Intel for labeling "LAN PARTY" Come on Intel, I love your unit but relax.

Feel free to ask any comments, as I was trying to be as fair as possible. Great unit, not for any gaming at all.

Pros: Install of win7 and ubuntu was a breeze. All hardware was supported in both operating systems. Used the m.2 and memory included in a combo deal (samsung evo 850, crucial 1600 sodimm 1.35v ram)

Cons: Failed after three months

Other Thoughts: All of the sudden stopped working: No bios post, no power LED.
I Will update my review to comment on Intel's handling of the warranty.

Update:
Intel's web system for warranty is a confusing mess, and it was not clear if they would have acted on my support request. I quickly followed up with a call that was painless and quick. A new unit was shipped to me immediately after they received my defective unit.

Pros: Compact and powerful

Cons: Has a sata hook up on mobo but need special adapter for power and it had no space in case for 2.5 drive. I ended up returning 2.5 drive and got a m.2 drive. The nuc5i5ryh has the space for 2.5 drive on lid

Other Thoughts: Great for mini pc to take with you to fix other computers and use in my living room as a media center.. Web surfer

Pros: Setup went flawlessly. Installed 8GB ram, Samsung M.2 250GB SSD, 1TB HDD, Windows 10. Literally took minutes to put together. (NOTE: Be sure to purchase the correct cable for video.) Installed Windows 10 from a USB stick w/o a hitch. This thing is quiet! It's also plenty fast for anything outside of serious gaming. All-in-all works like a charm.

Cons: None as of yet.

Other Thoughts: Still waiting for a "charging top" to be made for inductive charging of cell phones.......

Pros: -Solid performance
-4k Playback
-Size
-Silent
-Power consumption

Cons: -Why mini-hdmi again?

Other Thoughts: I'm using it with Kodi on Windows 10 and what a little great computer. It is silent and discreet but have a nice look. The performance is excellent and it can deliver 4K content easily from Kodi and IE, yes i know, why IE? Because chrome seems to throw all the playback of the processing to the CPU and not taking benefit on the integrated Intel HD... Even with tweaking in the hidden settings don not solve the problem. The only complaint is the use of mini-hdmi port that could be easily switched to a full-size hdmi cable like in the 6th Gen NUC.

Pros: Extremely small form factor, fast enough for general use, can drive any size monitor, quiet compared to most computers, solid construction.

Cons: Four USB ports on the back would be nice and there is enough space for them. An "ultra-quiet" fan profile would be helpful. On the quiet setting, such a small fan still produces a noticeable whine.

Other Thoughts: Bought this and put in a 500GB M.2 drive along with 16GB of DDR3-1866 memory to use as a HTPC, replacing an old clunker that made so much noise you would hear it over the movies. This box is great. It is much heavier than you would expect due to the very solid construction, but I'd call this a good thing as it won't slide around when you plug in to the front ports.

Loaned it to my wife to use as her new desktop PC while we are looking for the best fit computer for her. It is driving a Dell 34" curved (3440x1440) monitor with no trouble at all up to 60Hz over DisplayPort. I don't think I'm getting it back now for the HTPC until the new Skylake NUCs are available and I can build one up for her making me a two NUC household.

Pros: I bought this pretty quickly without reading carefully.

Make sure you realize that you need to buy memory and a m.2 solid state drive..

Cons: Haven't tested yet. Need to buy memory and hdd

Pros: * Easy setup.
* Fast!
* Quiet!
* Cool.
* 8 channel sound.
* HDMI and DisplayPort
* Packed with features: WiFi, Ethernet, Bluetooth, Infrared sensor, etc.
* Very small and versatile.
* Inexpensive considering the power and available features.

I purchased this to build an Ubuntu server running a Plex server to connect to my Synology DS413j NAS. I am very satisfied with my choice. All components are working very well together.

Installation of the RAM and SSD were very simple. When you take off the bottom of the case, all of the slots are accessible.

Between the NUC itself and the M.2 SSD, it's a beast in a tiny box. I expected to multitask with research during the install reboots. Ha! Nope. Too fast.

I am very happy with this NUC. It rocks as a Plex server. It transcodes without breaking a sweat.

I give a big thank you to the previous reviewers in helping make this decision.

Cons: None that I have found. Really... I can’t even be nitpicky here.

Other Thoughts: If you put the BIOS update on a USB and boot the NUC with the USB plugged in, the NUC will automatically install the upgrade. If you don’t realize that’s what it's doing and you turn off the NUC before the update is done and it won’t boot correctly afterward, boot with the USB plugged in again. Not that I did that or anything. I mean, that may have happened. Just sayin’. It turns out that when the power switch LED blinks steadily indicates its updating the BIOS.

From what I read at the time of my setup, Ubuntu 14.x does not support the Intel HD Graphics 6000 so I when straight to 15.x and it worked fine.

>>> This model only supports the M.2 SSD. It’s too thin to fit a 2.5” SSD. The NUC5i5RYH (the H version) is slightly taller and supports both M.2 and 2.5” HDD/SSD.

Quick technical summary of my setup:
Installed Ubuntu server with Xubuntu and XRDP.
Remote Desktop from my Windows to finish setup.
Configured my router’s DHCP to always assign a specified IP to the NUC.
Configured the DS413j to accept an NFS connection from the NUC IP to the video share.
Configured DS413j to send UPS statuses to NUC IP.
Configured Ubuntu to mount the NFS on /mnt/video.
Configured Ubuntu NUT (Network UPS Tools) client to listen to the DS413j UPS status. Plug the NUC in the same UPS with the DS413j.
Installed Plex server and added libraries to use folders found on /mnt/video.
Enjoyed the NUC/Plex as it transcoded old and new codecs seamlessly and without strain.

Pieces parts:
Intel NUC NUC5i5RYK
Crucial 8GB Kit (4GBx2) DDR3L 1600 MT/s (PC3L-12800) SODIMM 204-Pin
SAMSUNG 850 EVO M.2 250GB SSD (80mm)
Ubuntu Server 15.10
Plex Server

Pros: I replaced my "small" htpc with this nuc and couldn't be happier. I was never happy with the heat buildup in my cabinet even with all the extra ventilation and fans I added. This little beauty is now mounted on the back of my cabinet with no heat worries. No problems with hdtv or 1080p video streamed from my server.

Cons: none so far

Pros: Gotta love the NUC form factor.

Little, powerful, quiet, and cheap.

Cons: Limited hookups, mini sized everything so don't forget a mini-dp or a mini-cdmi cable/adapter or your gonna be waiting to use it

Other Thoughts: we make a fanless sealed version of the NUC for industrial clients, very high reliability.