There are only 2 exceptions on my hard drive that are full colored:
Nise Midi Doronokai. His artwork is epic. Period. There is no opinion, his stuff is
epic. Just look at this cover:
And the other exception are the "costume parfait" doujins involving Kyou from Clannad. I <3 Kyou ^_^
Rest of the time, I'm fapping to black and white stuff. In any case though, both have shown tremendous amounts of improvement in artwork and detail over the years, and it just keeps getting better and better. ^_^