Summary: After several devastating HDD failures, I caved last year and bought this standalone machine that could perform RAID5 for less electricity ($$) than a RAID setup through a PC. That was the primary reason, but I soon learned all I had been missing out on in the years I did not have a home networked storage device. The DSM software that runs on the DS431j (currently at version 5) has a ton of bells and whistles that make this model even more worth it's substantial cost.
Summary: I wanted RAID 5 and this is one of the least expensive 4-drive bay options out there. So far, I'm quite happy with the purchase. It is, as others will point out, slower than plus options from Synology. But it is quiet, simple to manage, Apple Time Capsule compatible, and full of features.
This product is insecure. Avoid this company at all cost.
6 March 2014
Summary: I own this NAS server for about 6 months. In the beginning it was all good. It is easy to setup, and comes with a bunch of optional packages that adds various multimedia features. Until recently, it started spitting weird warning message when I logged in from ssh, saying that it fails to load LD_PRELOAD library /lolz/jynx2.so. I was alerted enough to realize it is very likely a rootkit infection.
Summary: I too think I am going to trade this up. I love the product, I just think it needs more muscle given what I want to do with it.
Pros: It's a Synology. The management interface is several multiples of awesome. Community seems great too. Hardware is solid, and for the most part easy to set up. Can find good documentation on how to set it up to backup to CrashPlan on the web.
Cons: I did read William P's comment before buying this, but didn't really take it to heart. The reason this is $220 less than the DS412+ is because of the hardware. There is so much you can do with this device that once you start setting it all up, you begin to realize there aren't enough hamsters turning the gears.
Summary: I looked into a number of NAS devices before I settled on this one. You can configure it in various RAID configurations as well as let the device select it's default RAID, which is what I let it do. I have (3) 750GB drives and (1) 1TB drive and the system handles it fine. There are also apps for Windows and Android for accessing the data. It took a little bit of reading to get them all installed and working but it wasn't difficult.
Summary: I contacted Synology initially to explore some of my concerns and while discussing with them my intentions it was made clear that the unit appropriate was a DS1513+ which I ended up ordering from New Egg.
Pros: Unit is small. Clean looking and fairly straightforward. When it comes to Synology there is no doubt their OS is what makes the brand a quality product. Set up was super easy on the unit. Thus the 3 eggs.
Cons: Of course, you get what you pay for. However, unfortunately with this one the 512 MB of Ram and the 1.6 GHZ makes it very difficult to use all the features it truly provides.
Summary: I have been dealing with large storage arrays professionally for years. I've always run at least one "server" at home, and a few years ago decided to build my own NAS functionality. I spent a small fortune on 2TB drives, a giant case, and PCI SATA boards. I put up with a noisy, always on server in our small apartment that couldn't easily be rebooted into other OS'es (after wonkiness with virtualization).
Summary: Overall, I'm absolutely delighted with this device as a home/personal/small group server. There are things that definitely be improved, but it's still a marvelous little 'prosumer' product. If you have an extensive legacy video collection (not H.264) some of the higher-end models can transcode video for you for streaming to set-top boxes like the Apple TV.
Pros: An exceptionally rich feature set. Shared network drives and RAID, of course, but also streams H.264 video to numerous devices like my Apple TV, can record and stream TV (if you add a compatible USB TV tuner), act as a network print server (if you have a compatible printer), record and monitor webcams, provides private 'cloud' style storage, backups for your various PCs/Macs, and much more.
Cons: Interface can be a bit sluggish, but is remarkably user-friendly (essentially a minimal 'Linux' desktop presented through your web browser.) There is still definitely room for improvement (for instance, I don't care for the insistence on double-clicking things as if it were a native desktop environment.) I would strongly advise the design team to curl up with an iPad for a few months to get a feel for highly polished consumer-friendly UI design.
Summary: So much more than your simple, standard NAS. This thing is amazing. I got 4 4TB WD red drives and it set up over a day or two. No worries for me cuz I went out of town for Christmas while it was formatting/verifying/etc. The UI is polished and intuitive. I was very impressed. Added the Download Station from the package manager and it works perfectly. Even downloaded the apps onto my Android so I could pause torrents with my phone while I browse the internet.
Summary: I was in the market for a home-grade 4+ bay NAS that wasn't rack mounted. After about a month of researching and reading reviews on various NAS, I finally settled on this unit. Setup was easy, if a bit time-consuming. Being one of the "cheaper" models, the drives are not hot swap, so you need to take the cover off, remove a drive tray, screw the drive to the drive tray, put the drive tray back in, and then screw the drive tray to the chassis.