Reception on the iBooks has always been better than on the PowerBooks. This is because the metal case impedes the signal. Basic physics.
As for the buffering issue, I've always noticed that notebook to router to notebook streaming very often incurs some buffering. I don't think you're alone with that. Remember, it's (probably) not streaming "directly" from your iBook; it has to go to back through the wireless router too. Depending on the speed of the router and the network traffic at a given time, this could cause small or large buffering delays.
Regarding the clicking, though, as long as you're pressing hard enough to hear that "click" sound, there shouldn't be any problems sending mouse down events. If you can regularly reproduce this problem, I would definitely suggest showing it to an Apple technician (easiest and cheapest would be at the Genius Bar in an Apple Store).