Reaper's Slip Mode offers something very special that is lacking in any mode in ProTools (and just about any other sequencer I can think of). When in Reaper's all-tracks Slip Mode, if you have tempo/meter changes, they will stay with the items you are moving around. This feature alone sets Reaper far above any other program for composition for me - anyone who composes with tempo/meter changes should take a close look at this feature...