Ok, how good of a QB is ben roethlisberger?

ok it seems there are many different opions on this. Big ben has bad plays and bad games, you know when he scrambles around with the football and then gets sacked several times in a game..cause he can't get rid of it, and when he overthrows people...there are a lot big ben haters out there..bu-t yet he's good at conducting game winning drives, and he's got 2 superbowl rings. He has the 3rd best winning percentage of any QB that ever played. so is he good?