Yeah, I just recently turned off commenting and user account creation on my non-profit website. It was too much hassle and no one ever commented anyway.Oh god yes. I do a few things to combat this:
1) Require a user account to post a comment - no guest comments, period.
2) Three Captchas on the user creation.
3) One Captcha on the comment posting.
It would be a lot easier to have no users, no comments. That's for sure.
I like blogger as well...though I've thought about migrating to wordpress. The issue for me is that blogger does domain mapping for free, whereas I'd have to do just a URL forward with wordpress, or pay for the feature.