The only difference as far as maintenence between the two is that a four stroke has valves that will need to be adjusted every now and then. It is very simple to do this. They have to be readjusted a couple of times during the break in process which is around a gallon or two of fuel, but after it's broken in, you'll hardly ever have to adjust them. It doesn't hurt to check them after several hours of running though. Once you go to a four stroke, I'll bet that you'll never want to go back to a two stroke.

John