Usually, if I start a story and the spelling and grammar are really bad, I just quit reading it. I just can't stand reading stories like that--the language distracts too much from the story--and anything I could say in the way of concrit isn't going to make much of a dent, anyway. So any spelling or grammar problems I point out in a review are likely to be minor. I generally spend more of the review talking about what I liked about the story, because if there weren't enough things that I liked, I wouldn't have read through to the end.