I actually like Bernadette and find her funny - her role as a sort of continuation of Howard's mother is hilarious, she has some great lines and delivers them well.
Some of the posts on this thread seem to come down to little more than 'meh, we don't want gurls in the show, they ruin it', which I disagree with. It's just Amy I find annoying, because the character is completely unrealistic in any way because she's overly caricatured beyond the point where there's any common ground allowing me to relate to her. I'd rather have Leslie Winkle back, intellectually sparring/getting into confrontations with Sheldon, that was far more interesting and funny, and she was realistic - that could so easily have been developed into a far more interesting hate/love/intellectual competitive type scenario despite her earlier dalliances with Leonard. Bring back Leslie Winkle!