i went from a valeo 17 to a P20 to a P30.....i agree that phase files used to have a "digital" look, which is why went with the valeo at first....but that changed and i feel that while leaf might give you a "more film like look" so can phase if you know how (which isn't hard at all).....but the phase can also give you a supersqueakyclean look that leaf can't IMO....
i think the P30 is the best back ever....if you consider, resolution, imagersize, senitivity, speed, workflow (not only in C1) qulity f the files out of the back, super relyable!!!!! (ask anyone) all for a reasonable price....it is hard to beat...i am sure that other backs can mach some of those things, but i don't think there is one that can compete with the whole package.....i doubt the other phase backs can either....
BUT either way: this is like kodak vs. fuji (in the old days) it comes down what YOU prefer....so do yourself a favor and test all systems.....if you are looking to shoot with a H, also check out the H3D31....same chip as the P30.....ready the forumposts, but these are all personal opinions....you HAVE to check them all out....if you like the dalsa chip....the sinar backs are amazing as well (almost went with that...instead of the P30....)