Re:
Front mechanical, that's a fair point. I've got x9 and x0 and the shifting isn't great. I recently downgraded an xo front for an apex or gx (I forget which) and it worked much better (and had a proper band rather than the endless band sliver of metal style).
I do like SRAM, but that said, the dual push Shimano are great. I've got bikes with both, and aside from trying to push an SRAM shifter the wrong way, am happy with both performance wise.
I've had issues with SRAM shifters. Design wise you can push them past their limit and the tooth that pushes the ratchet round can break off. Never done it myself but have bought shifters that have been intermittent, and once opened up, found this to be the cause. Seems a flaw in the design.