Congratulations on seeing the light. Two strokes are much easier to own, and operate. I'd say you're likely not to have many issues, but things to check would be the condition of the chain. That'll be the first indication of how the owner took care of the bike. If it's new, cool, move on to the wheel bearings. Grab the bike with one hand, and the other grab the top of the whel and try to move it side to side to see if there's any play. Worn wheel bearings will show up in side to side play.
Getting a used bike is always a grab bag. Sometimes you get a new looking bike with lots of wear, sometimes you get a bike that looks pretty used but is well maintained, and everything in between. The good thing is, if it runs and feels good, anything that could be wrong with it will be inexpensive and easy to fix.