Cool! This will be my first time betaing, but I have attended writers workshops and done that style of critique before, so that's where I'm coming from.

Re: grammar, I have to admit, I pay a lot more attention to whether something sounds awkward than to grammar per se (everything I know about grammar, I learned from the process of learning French...and from reading Language Log for a while, where all the linguists are generally on the non-prescriptivist side of things and talk a lot about language as it is used rather than language as it is ruled...)