One of my friends used the MP product on his CJ, the booster gave up after 2 to 3 years. We replaced it with the Navaho booster/MC from Off Again 4 Wheel Drive, it's much better than it ever was. The Vanco product is excellent also and, as Jeepskate says, he hangs out on here and is very helpful, even if you don't buy his products. Either is an easy bolt-up and bleed the brakes, all needed parts are included. Really big difference in stopping with their duel diaphram booster and bigger M/C.
'81 Scrambler w/ FI 360 AMC, 33x12.50 BFG M/T's, 5" of lift, ARB'd Dana 44's F & R, Dana 300 clocked & twin sticked w/4:1, Warn XD9000i, etc...
2002 Grand Cherokee Limited, 2008 Overland Grand Cherokee, a 1976 CJ-7 in pieces and 3 more off-brand 4x4s...............