I can't say I've had experience, but they've been around for a few years and haven't heard any complaints about the company, so it's probably a safe bet. The 1793 based unit looks nice, and isn't too complicated for a new DIY'er (if I may so presume). Have you done SMD work before? That's probably the most difficult part of the kit(besides the casing that is..) There are some good SMD how to vid's on the net though.
This one http://cgi.ebay.com/great-USB-valve-TUBE-DAC-kit-recommend-/180558388822?pt=LH_DefaultDomain_0&hash=item2a0a1e5e56 also looks intriguing ... quite a bit more complicated, due to requiring multiple power supplies though. Love the idea of being able to us Tube output if you like.
You should also have a look at the Gamma 1 from AMB http://www.amb.org/audio/gamma1/
It's very well liked by many on HF, and you'll definately benefit from the wealth of experience that the users have here on it.. (It was my first dac build, as part of a Gamma2, and have a 2nd in the works for a second gamma2). My first experience with SMD also, and only had one small issue with it that was fairly easily resolved. You need a couple of extra items if you are going to do SMD work though, such as a Loupe for inspection, solder wick and a flux pen..
Not strictly a kit though, you'll have to order parts from Mouser or Digikey yourself, after you buy some of the basic bits from AMB's site
If you want to do strictly an optical/coax version with no USB, you can keep the costs down too..
