I bought an RT charger for my Ladyfriend to keep at the office for her Pro. With "normal usage," the RT charger will power the Pro and maintain the battery charge. (Scientifically proven, right here on my coffee table.)
I also read that the Pro charger can be used on the RT. I bet it would charge a lot quicker with 48w. But for me the Pro charger price is too high when I can get by with the 24w RT charger. Might be something Pro owners would want to consider, i.e. buy a RT charger for their Pro as a secondary charger and save some cash.
Well I picked up a second MS RT charger at Staples today for when my RT is at work (which is a daily) . If I fully charge it at home it can last almost two days but now I don't have to remember to charge it. .