I rarely use 2-strokes anymore, but when I do, the three things I notice most are:
1) The crappy toy-like sound
2) higher fuel consumption
3) the God-awful slimy mess they leave all over the airplane!
Once you go 4-stroke, you'll never go back - unless you LIKE that slimey mess
Now before the 2-stroke guys jump all over me, i will admit that 2-strokes have their place. That place is not in any of MY airplanes if I can help it.