To follow-up, SRAM's concept seems a little more intuitive to me (the Shimano RDs still are free to rotate how they may, but the SRAM RD is pretty tight where that B-screw sets it). I'm considering converting an old MTB I have from Shimano to SRAM (either X5 or X7) and I'm curious if those RDs will operate and adjust similar to the X3 on my wife's hybrid.