I brought this kit from Mr Nixie in June 2012, and have only got round to building it in January 2013! I wish I had built it earlier, it is brilliant, I absolutely love it. It's very well thought out and made.
At this present point in time (January 2013) ... has run out of Sven kits, but it seems a new version is coming out!
I have also brought the GPS synchronization option with it, this seems to work really well.
The RGB leds really bring the clock to live, they very subtlety change colour. Even in the factory default. There are a myriad of options for them, I have yet to try them all out. There is a built in temperature sensor, which gives the current temperature of where the clock is placed, this is displayed every few seconds, another great feature.
Following are a few pictures of the build, this should give you some idea on the skills required to build it. The last couple of pictures are not wonderful quality, I did not want to use the flash, but at the same time too lazy to get the tripod out, I wanted to give some idea of the ambiance of the clock.