I've rarely if ever experienced a buggy skill shot. Perhaps you're playing with a higher ping than me?
Yeah, the pvp.net client is laggy -- that's one of my few complaints left about the game. There are a few bugs still in gameplay. I've been stuck against Anivia's wall once or twice, and Alistar's charge can get him stuck sometimes. For the most part, though, my games are bug-free. All of my champion's skills work like they're supposed to when they're supposed to.
The most important part is that the gameplay is fun, and it has been fun for a long time. All of these minor bugs can be fixed through time.
For the average gamer, I think this game is ready to hit the shelves. I guess open beta will really show us whether it's ready or not.
The skillshot issue has been around for quite awhile. Search the forum.