Just finished my first build of a VP312 VPR-Litz, no problems, works great. I had to ignore the recommendation from Jeff to bring it up with a known good DOA, since I also built the CA-0252 kit, and that's all I had, but all the static checks of the VP312 were good, and it seemed to power up in the rack ok without a DOA (i.e. no smoke or fire). So I just plugged in the DOA, powered up the rack, and held my breath. :-) All good...
Kudos to CAPI for clear documentation, and a well packed and labeled kit. I would maybe hesitate to recommend the CA-0252 kit for a first time DIY builder (I think Jeff has stated the same), but if you have decent solder skills and the right tools (REALLY important!), the VP312 is a straightforward build. The CA-0252 is really no harder, just things are a little tighter, and poor soldering skill is more likely to cook a transistor than a passive.
I've tested a bit with a couple of different mics, on different sources, and overall I'm very pleased with the sound. It's certainly got a desirable 'color' that I don't have with any of the other pres I own.
I've got a second one to build now, and I'm thinking of taking some photos and creating a more formal, VP312-specific (Rev B) build guide if anyone has any interest?