This is the review I did for the previous model, the 209j. I'll explain the differences afterwards:
The great thing about the Synology drives is that they all use the same software (virtually - variations in e.g. number of IP cameras that can be connected).
Although this is the lowest power drive in their line-up, it still has all the capabilities of its larger siblings.
I bought this when my old Western Digital NAS died. It was a fully enclosed unit, so when it died I couldn't access the data that was stored there. In comparison, this has removable drives (2 set up in RAID-1 format). This does everything for us: we've plugged USB speakers into it, and it is our primary stereo (it can also stream music, so I listen to it through headphones at work). It backs up both laptops continuously, and acts as a mini web-server, hosting our photos for family to see.
The one down-side is that this is just a little under-powered: If playing music it can't do much else without starting to stutter. In theory these boxes can be used to stream hi-def video to a TV. No chance with this one.
My other complaint with Synology is that they seem to assume a little too much prior knowledge in their user manuals - sometimes they seem to be along the lines of "The DNS configuration tool is used to configure your DNS settings." without actually telling you what that means or why you might be interested.
In short, I have become a fan of Synology, but next time I'll get a slightly higher-powered one, and use this a back-up.
So, the 209j is slightly underpowered, but is still a great piece of kit. Since I wrote the above review, new firmware has been released which goes a long way towards improving the helpfulness of the menus.
Now the comparison: