Dai. I develop C41 films with Caffenol all the time, Kodak Gold 200 has been my test vehicle, since I got a case of 58 films on the -bay. Caffenol acts as a pretty good B/W developer on Gold 200. I have had some difficulties with other brands, especially Fuji, and havent pinpointed why yet, got a case durn cheap of Fuji on the Bay too.
I have developed chinese B&W with great succes, both Lucky and Shanghai, 35mm and 120 respectively. Caffenol works as a compensating finegrain developer that gives you full ISO, the compensating part says it will also faciliate push processing, but I'm not currently into that, that was the 1970's and "super developers" thing for me.
I also tried Kodak Advantix film, from an APS camera. Here the amazing thing happened. the B&W developer did yeld color negatives! I'm still very, very surprised by that and will do some more tests. Had to modify an old tank (5 minutes work) and the hard part is breaking open the APS casettes without damaging the film.
Caffenol is very easy to use, except for some strange films reported by others, you can more or less mix and match fims in the tank and develop all just the same.
There is a group on APUG, just like this for Caffenol, in there is also a link to a blog in Germany, run by Reinhold, its in english, read all you can, especially Reinhold has his head screwed on right and backs his claims with excellent pictures, as are my negatives, excellent, but being modes I don't like to show technically perfectly developed picture disasters.....