I'm sure I overlook some typos and punctuation errors, but if it gets so bad that I start thinking that even I could do a better job, I hit the back button.

All in all, I'm most interested in "good" characterisation, though. I like to see how a character behaves and why he does so. I want to understand him and see him develop. For me that goes hand in hand with the characters not being OOC, but I realised a long time ago that what I regard as OOC other readers / writers don't regard in the same way and vice versa.