Pros: -Good for less than a dozen users
-supports plex, can plugin directly to your hdtv, has a boat load of features and apps to make managing the device a breeze.

Cons: -Not enough CPU power to do transcoding.
-After swapping out the RAM from 1 gig to 8 gigs, i no longer get out of memory crashes and I am able to use the server from multiple devices concurrently. If you don't upgrade, you will eventually get out of memory errors (I was getting 1 to 10 every day.)

Other Thoughts: The Qnap ecosystem and the setup is very painless and amazing, however this particular product has poor performance if you don't add RAM. After upgrading from the default 1 gig to 8 gigs performance is much better. The CPU is limited but sufficient for the half dozen concurrent devices I have.

Pros: HDMI and transcoding add value to NAS features running RAID-1 with 5TB drives with no issues. HD station updates have made the system essentially an HTPC replacement. Will expand the memory eventually - nothing from Synology compares at this price

Cons: 1GB memory may cause updates/installs to fail. Malware detector indicates it removed something but doesn't go deeper as to what and where,

Other Thoughts: Plus version with quad-core out, maybe the extra bells/whistles would've been nice

Pros: many bells and whistles, easy setup, active firmware updates, nice NAS for the money. Security settings make it easy to keep bad guys out. hdmi output

Cons: It failed in less than 2 months. This was disappointing.

Other Thoughts: Have a TS-453 and the TS-251 was bought to become an offsite backup. Rsync was a breeze to setup.

Manufacturer Response:

Dear Randy K.
Sorry to hear about what you are currently experiencing with our TS-251, as this is not the intended or typical experience with the device.
We will work closely with newegg team to provide you better shopping and product experience
For your case,
after 30 days of purchase, please contact QNAP technical support directly
we will arrange a new unit for you

If our support team can be of any assistance to you, please contact us via email or phone below and reference this Newegg review.
(909) 595-2782
http://www.qnap.com/i/useng/about/con_show.php?op=showone&cid=1

Pros: It didn't work, so no pros

Cons: DOA basically. It showed up and the networking didn't work. It would get an address by DHCP but then constantly fall off the network a few minutes into the configuration process.

I tried DHCP and a static address. I tried both LAN ports on the back. I tried resetting to factory defaults. I rebooted it. I rebooted the switch. I tried wired and wireless on my laptop.

Nothing worked. The LAN light will blink and then stop, blink and then stop, repeat. And then the alarm will just buzz randomly. I don't know if the unit is rebooting or what.

I work for an IT services company and we recommend QNAPs for small businesses to backup to. But how can I, in good conscious, continue recommending them after my own personal device was DOA?

Other Thoughts: So disappointed.

Manufacturer Response:

Dear Michael L.,
Sorry to hear about what you are currently experiencing with our TS-251, as this is not the intended or typical experience with the device.
We will work closely with newegg team to provide you better shopping and product experience
For DOA case,
within 30 days of purchase, Newegg can return or replace a unit for you.
after 30 days of purchase, please contact QNAP technical support
we will arrange a new unit for you

If our support team can be of any assistance to you, please contact us via email or phone below and reference this Newegg review.
(909) 595-2782
http://www.qnap.com/i/useng/about/con_show.php?op=showone&cid=1

Pros: I have been using this product for about two months now. It is a great product and was easy to setup. It's fast and does all it was advertized to do. I have no problems so far with speed. The apps are easy to use.

Cons: N/A

Pros: This is my second QNAP. My main NAS is a QNAP TS-459 Pro + which I have had for a few years. It backs up automatically to my new TS-251. I upgraded the TS-251 with 8 GB of GSkill memory (details in other thoughts) and run the TS-251 as a NAS and Media Server through Kodi. The TS-251 was far cheaper but boots faster than my older QNAP. Transfer speeds are excellent between the two systems. There is never a lag when watching movies. The QNAP web interface takes some getting used to but is very logically laid out.

Cons: Not really a con but this QNAP has two bays. I am running the TS-251 with two 3 TB in RAID 0 so if one drive fails all data is lost. I am OK with this as I depend on my TS-459 which is in RAID5 as my main storage.

Other Thoughts: Based on recommendations from other posts I upgraded the memory to 8 GM. The maximum memory is 8 GB although I have read others have gone up to 16 GB. The QNAP operating system is very efficient and with 8 GB the system at idle is using 9%. Memory I used: G.SKILL Ripjaws Series 8GB (2 x 4GB) 204-Pin DDR3 SO-DIMM DDR3L 1600 (PC3L 12800) Laptop Memory Model F3-1600C11D-8GRSL

Pros: First NAS I have. Perfect match for Smart TV too.

Cons: Only 1GB memory.

Pros: after read couple reviews, i decided to purchase TS-251
i decided to purchase this on my favor store newegg.
Will call pick up in 2 hours -quick
setup and configure- quick
transfer speed 100MB/s- quick

Cons: none so far

Pros: I purchased this NAS with Plex being nearly the only motivator. I was running Plex off of my gaming rig which was less than power efficient. I was a little concerned, based on what I read, that it wouldn't have enough computing power to perform the on-the-fly transcoding that makes Plex streaming work so well. I ordered the model with 1GB of ram because I knew I had a 4GB stick laying around. The upgrade was very easy! Just a simple screwdriver will do the trick. So at first I thought it was incredibly slow (specifically Plex). Once the NAS had finished downloading all the metadata it sped up dramatically! Since then everything has been really smooth, including transcoding. Also, the NAS automatically configured all port forwarding on my router/modem. Overall this thing has been well worth the money!

Cons: I really would have liked to see toolless hard drive installation. I also would like to see a better UI while utilizing the video output vise just the multimedia view. I would like to see the same sort of interface that is used in the browser without having to open Chrome.

Pros: I have a WD My cloud (cheap and pretty good NAS) and I have 2 Seagate Black Armour NAS 4bay (really hate them both).

And then I came across the new line from Qnap and the TS-251/451 series NAS and I suddenly realised that they others are obsolete. Between the ability to upgrade the RAM for $30-50 for 8gb of ram and all the amazing apps included at the touch of one button...... Its stupid to consider any other NAS imho.

I was lucky enough to come across an open box TS-251 here on NewEgg for half the original cost and, i'm just guessing its the 1 egg rating down bellow, (so thanks)! I put 4gb of RAM in it and 2- 4tb WD reds in it, and its amazing.

Originally I got it because I run a Plex media server with about 2tb of media in every resolution and file format you could imagine off of a built windows rig, but now my NAS does it just as good if not better. I have it transcoding everything flawlessly to every device I have. Even my little brother 2,000 miles away can stream at full resolution while 3 or 4 other people are also streaming at the same time.

I'm just now getting into the surveillance apps to record my IP cams, and yes its working perfect.

It even did most of the port forwarding for me, yet I had to manually set it up on my 2 other brand NAS setups. So that was another huge plus. I even used different ports on the Qnap.

Cons: none

Other Thoughts: Just buy the Qnap TS-*51 series in the 2 or 4 bay and dont look back, and you can thank me later.