The main difference i think is that rebound ace is a rubberised surface whereas Decoturf is cement. Decoturf is faster because the rubbery rebound ace surface holds the ball a bit longer (sticky rubbery nature). i actually haven't played on rebound ace so i wouldn't have a clue how it REALLY does play (i was supposed to play in the media tournament at the AUstralian Open in 2000 but it got rained out).
I highly doubt that the surfaces will be replaced with the other at the respective slams.
Yes, Rebound Ace is better for getting your foot stuck in the sticky surface, causing a severe ankle injury! Just ask Lina Krasnoroutskaya and many others. Lina had her year ruined and maybe her career by those dangerous Rebound Ace courts!
Happiness is like a cat. If you try to coax it or call it, it will avoid you. It will never come. But if you pay no attention to it and go about your business, you'll find it rubbing up against your legs and jumping into your lap. - William Bennett