I've used 2 Chilipower batteries (alongside the original Fuji battery which came with my camera) for almost exactly a year now, ~12000 pics. I've been pretty careful to use each one about the same (batteries are numbered 1,2,3 and used/charged in order) so not like any one was more used than the others. Number of shots per charge from the Chilipowers was about the same as from the Fuji..didn't notice any difference anyway...
BUT now the Chilipowers seem to have lost their shape - don't come out of the battery slot without having to shake the camera and the sides seem to have bulged a bit. No harm done as far as I can tell but decided that I didn't want to risk a permanently stuck/bursting battery..changed to original Fujis now so now using 3 Fujis....