Summary: ... this is not one of them. I regret not getting a bigger model perhaps, but otherwise there is nothing I can fault with this device, and now about 2 years on, it continues surprising me. Synology's software and updates are excellent... the device gained so many features since buying it that I have found that it saved me more and more money as I could cancel other services. (Google Drive etc). Low maintenance, reliable, easy to use and powerful features...
Summary: I like tech stuff but I am not an expert. This is a great server to get all your stuff backed up on. I used it at first to protect my research data but now that I published my data don't need to protect it. Now it just backs up my computer. With my mac as long as I am on the network, it automatically backs up. It is great. UPDATE April 2014, After a few years of working I had an issue with my server. Initially I thought the server had encountered an error.
Summary: The processor could do with more oomph. Not ideal for running Plex in spite of what Synology claims and allows via their software. Would not recommend for streaming movies with the onboard software AT ALL.
Summary: I haven't had any trouble with this at all. Running Mac OS 10.6.8 and the NAS is attached to my LinkSys router. Transfer rates are great and the volume shows up in Finder, and since I use Photoshop, Bridge and can easily be used as another hard drive. I also have used it for Time Machine backup. I haven't played with any of the other features however.
Summary: I had previously ordered a ZyXel NSA325 based on good, competitive online reviews and the fact that it was 1/2 the price of a "comparable" Synology model. It wasn't a bad unit but it didn't meet my expectations at all so I returned it and got the DS212 and immediately I'm impressed with the differences.
Summary: I was in the market for a redundant disk drive (something that could recover from a single drive failure). As I reviewed products I weighed the advantages of a networked storage array versus a simple usb based approach. If I had one pc to backup I would have gone with a simple usb based array. However, I not only needed to backup my computer but also those owned by my wife and kids.
Summary: After reading rave reviews about the Synology NAS 212, I decided to buy the product. I put two Seagate Barracuda 3 TB drives that I bought at amazon into the NAS. I connected the NAS to the gigabit port of my router. After configuring the NAS to use SHR, I decided to try and move my pictures and music from the laptop to the diskstation. I was shocked to see that my transfer rates were only about 2MB/s. I was expecting transfer rates closer to 30 MB/s.
Summary: This is my not my first NAS purchase, but it is the first one that I didn't return. The unit itself is elegantly designed and is very quiet. The speed is as expected, although you might want to invest into some more CPU speed and RAM if you plan to do a lot of 3D movie streaming (It works just fine for HD movies). The big selling point, as others have pointed out is the rich features that come with it.
Summary: After living with a ReadyNAS for 2 years, switching to the DiskStation was an excellent choice. The DiskStation user interface software is significantly more advanced (ease of use, options, etc.) than that with the ReadyNAS.