I can't think of many (if any) champo GKs who are better than Steffan with the ball at their feet. He makes misplaced passes (which may be a concentration issue) and the QPR goal was a big mistake. Didn't realise it was so far out and that wide until I saw it again on the MFC site. However, I will give him the benefit of the doubt and put it down to general rustiness as he hasn't played regular first team football for about 3 or 4 years. I think this affects goalies much more than other players.
I think he will hopefully learn from his mistakes and has generally got better as the season has gone on. It's just that he is still making the odd mistake, but his general overall play is good. Certainly for the style we play, no-one is better.
Schwarzer was the best Boro keeper I have seen. Dimi had a good defence in front of him and didn't need to make many saves. Randolph an excellent shot stopper. However nowadays, you need to be good with your feet as a GK, and Steffan is easily the best we have had at that skill.