I keep a 75G tall acrylic show tank in my home office with Mbuna and syno Petricola cats. I started 18 months ago (April 2014) with 3 groups, Maingano (Ps. Cyaneorhabdos), Metriaclima sp. Membe Deep, and Labidochromis Perlmutts. The Membe deep group is down to 2, a single male and a female who haven't bred. I rehomed some males, and lost one or two females to agression. I've got 4 Perlmutts of indeterminate sex. I think I have a male and 3 females, but they haven't bred and it's hard to really tell, they're not the dominant species in the tank. That'd be the maingano. 7 of them in the tank, the largest male is the tank boss now after I removed a particularly nasty Membe Deep, and he's fairly mellow. They breed like crazy. 4 of the 7 are second generation fish, and currently two are holding. I've rescued at least three fry out of the bottom of my eheim canisters when cleaning them, and 2 of them are still around in a growout tank. After a bunch of rehoming, I'd gotten down to around 12 fish in the tank, and the aggression was actually worse, as I had several fish living in the upper corners of the tank too often. I added a group of tropheops elongatus Mbuna that I picked up from Geiler Aquatics, and as a group they've totally calmed the tank down and they look great mixed in. They were an excellent pick up that turned out better than I'd hoped!
I love the activity, the tank stays pretty algae free with a Current LED freshwater+ light on it, and the Mbuna are always good for a show at feeding time. I have some west african Kribensis in a 29G as well, and have just finished setting up a 40B for a Tanganyikan tank as well.
I live on Bainbridge and am on a shared well, so my water seems to be opposite of the Seattle water out of the Cedar and Tolt river watersheds. It comes out of my tap at 7.7 or so, with about 8 degrees total hardness and 7 deg carbonate hardness, so it seems to be pretty solid water for them, although I do add a bit of baking soda and epsom salt to the big tank at water changes, which they seem to appreciate.