Pros: The size of this device for what it can do is incredible! It has an incredibly small footprint and could fit on a desktop if needed. I managed to hide it behind a 24 inch monitor on a desktop. It also seems to be quite light on power consumption. I have it plugged into a rather small UPS and when our power went out the system continued chugging along for nearly 15 minutes before finally shutting itself down. The DL4100 has an LCD display that gives a brief status of different system information like active network connection and storage status. The system came set up for RAID 5, which is perfect as it protects against the failure of a drive to protect the integrity of your data. Setting the system up was VERY easy. I literally just plugged the device in, connected it to my network, and installed the iPhone app and was on my way to backing up my data. I used this device mainly through OS X Yosemite and it was a breeze. I was able to backup my music and movies with relative ease. I tried to use the device for as long as possible and asked for more time to review the product than the standard two weeks given, but I still have not been able to use all of the options available to this device.

I used to think of myself as a semi-savvy technical guy but after using this device I have been humbled. Though this device would be perfect even for a non-technical person to use as a backup device there are SO MANY options for the advanced user. The different options and settings had me literally rambling to my wife (she is so very patient with my geekiness) about all of the different possibilities of this device. I can share different folders with a simple e-mail of a link, remote access different folders or individual files. I was unable to fully explore the options in the given timeframe for my review (I love being an EggXpert SO MUCH! Newegg is a geek's motherland and being able to review these products is like CANDYLAND!) even having asked for an extension.

You can upgrade the system's RAM all the way up to 6GB (though the included 2GB has been plenty for what I've been using it for). There is a USB port that you can connect a USB hard drive and with the touch of a button do a complete backup. That feature was SO HANDY for all of the different external drives, USB stick drives, and external hard drive cases that I had laying around. I found old pictures I'd completely forgotten about just because I was treating this thing like Johnny-5 (MORE INPUT!).

I can only imagine how amazing this device would be for a small to even a medium-sized business. It can manage networked CAMERAS! I didn't have any compatible cameras to test this feature out on which was one of the main reasons I asked for more time for this review. I only have a baby monitor at the moment and some webcams and none of them were supported, however, WD's website claims to support like 30,000 cameras. I was unable to find any cameras to borrow from my friends and didn't have time to order one before the holidays to test it out but the implications for home security and especially for a business is AMAZING. This little tiny device does things I only thought were possible with one of those giant server racks that fills up an ENTIRE ROOM! Did I mention that I'm totally geeking out here?

Cons: I literally have NOTHING bad to say about this device. It doesn't even have one of those annoying bricks on the end of the plug! There are SO MANY THINGS this little piece of technological heaven can do. I would never have purchased this for myself but after having used it and only BARELY scratched the surface of what it can do I can say with complete confidence that I WAS A FOOL! If you are considering a device to backup your precious data GET THIS NOW. It is absolutely amazing. I know this is the "cons" section but I have turned it into a "Totally Geek Out" section.

Other Thoughts: You can access this device over your mobile devices with apps for your smartphone, tablets, MacBooks, Macs, Windows PC/laptops, Refrigerators (I don't know for sure about that last one...I have heard that there is a Smart Refrigerator with internet access and if that is true I bet you can backup your fridge data to this device).

You can set up to receive mobile alerts as to the status and health of your network.

As a final thought I tried to prepare myself to write a very technical and detailed review but wound up just seeming like some kind of babbling fanboy...which is strange for me because I am not easily "wow'ed". I guess it is just the fact that I have those two or three friends who have built their own servers who talk about all of the amazing things they can do with data storage, managing their networks, etc. that seem like they are setup like some giant business instead of a home computer system and I've always wanted to build myself a setup like what they have...and in the space of FIFTEEN MINUTES and plugging in two wires I have ALL OF THE SAME FEATURES that they do and for a tenth of the price! I believe I may even have GREATER CAPABILITIES! MUAHAHAHAHAHAHA! (Was the evil genius supervillain laugh too much? Yeah...sorry about that.)

If you have a small business...heck even a large business or the desire to setup a reliable and highly organized home network that you can build upon over time and learn and explore and expand upon as you discover more and more amazing features you MUST GET ONE OF THESE THINGS! A friend of mine just started his own business and I have been extolling the virtues of the Western Digital DL4100 to him and I will not stop until he has gotten himself one of these marvelous machines. As always a shoutout to Newegg as well. Hail to the kings and queens of tech, baby!

Pros: Supports up to 24 TB In Size
Accessible over the network through dual-NICs to increase performance.
Supports dual power supplies for backup purposes
Supports auto-backup of files for data loss prevention
Supports media center, FTP, torrent, web server, and several other features allowing you to use this as far more than just a simple networked attached storage.

Cons: I only have one issue with this unit and it is when transferring files. Using the USB 3.0 ports, I tried to transfer data to using an external hard drive. The order to copy was sent from a laptop with only 802.11g Wi-Fi. The result was a transfer speed of 8 MB/s. Trying to do the same thing via a LAN connected PC resulted in 70 MB/s. This means that when issuing an order to copy from the USB drive that it first routes the data from the drive, through the network to your PC, then back to the NAS. This is not very efficient, and really quite pointless. It seems that WD could have implemented some sort of direct copy solution from the USB drive to the internal drives, but there is not one I can find.

Other Thoughts: Other than that issue, which isn't a major issue really as you can transfer files from a PC without any problems, the NAS works perfect. I love this thing, and honestly as soon as I get the spare cash for it 'm tossing two more 4 TB drives into it. having a central networked server, and really this is a server not just NAS, is extremely convenient. From data protection, to sharing data, to the services the server can run itself like listed in the "Pros" section, this is the most helpful piece of hardware I have ever had.

If you need a device for these functions, don't even hesitate. Buy it now, you won't have any regrets.