He's not terrible by any means, just not great. He's made quite a few mistakes already so far this season. Saw 2 today and I barely watched 5 minutes of that game. Though it's hardly surprising coming from the SPL. There was a stat on SSN a while back that said he averaged 1 save per game in a season at Celtic, heh. He's still relativity young so obviously has a lot of room for improvement, and as frustrating as Krul has been in recent years, there's no way I'd take Forster back to be #1. £10m was ridiculous money, too.
Courtois, De Gea, Hart and Lloris are all light years ahead of him.
Courtois, De Gea, and Lloris I agree are better goalkeepers that Forster, but I do not think there is that much between him and Hart.