Well, today aside, TEB is the way to go. Yes, it can get crazy busy at times, but all the FBO's and the tower are very, very used to it and all operate under those conditions better than any other airport I've ever been. 99% of delays at TEB are caused by delays at EWR, probably one of the worst airports for delays in the entire country...even Northwest Airlines site lists the on-time rate of 50%.
LGA is ok, but the FBO is awful, inconvenient for pax due to being far from the aircraft and they (sheltair) never seem to know what the heck is going on with the pax transportation. And, you have the unpredictable Queens traffic to deal with on the way to the city.
Look, TEB is busy for a reason-it works better than any other and it's closer than the others.
HPN is ok, MMU is also-if distance isn't a concern.