Justin is very young and new. You gotta give him some credit for what he has done at his age and no entertainment experience. Lady G. is little more mature than Justin. The two don't compare. Just my opinion don't bash please.
Reading the title and the arguments in this topic amuses me. X)
Back on topic, I'd go with Lady Gaga. Justin just sucks. I'll give him credit though for managing to break out and get popular since today's industry is pretty tough.