I use the Yahoo CSS framework. I can't compare directly, but if you are just looking for grid, reset, and standard font functionality, I don't see why you would look beyond Yahoo. They host the files, they have done intense optimization and testing, and they have good browser support.

I've used both, and Blueprint is way ahead in terms of design sense. It also doesn't require obscene amounts of nesting. The constant attention to the baseline is a huge win (the Blueprint links to relevant authors about using it in design).