My MTB has "Rapid Rise" and is the only bike, out of 3 geared bikes that does. I only have it as I got the groupset and wheels cheap from Merlin Cycles. Erm, I don't find them any more or less confusing than normal gears, they still work. I guess if you're used to gears working ina specific way then it might confuse you but, probably due to the 3 bikes having different shifters (Ergo, bar end and dual control), I don't seem to get confused.
So: no worse, no better, just different.