User Stats Plugin?

I’ve done a lot of searching but haven’t found what I’m looking for. Does anyone know if there’s a plugin that gathers my users’ (subscribers) data nicely? I’d like to be able to see how many comments they’ve left and when they’ve registered. The ‘Users’ page only shows how many posts they’ve made (which is none for everyone but me).

This would be useful for 2 reasons: 1, I could purge spammers and users that have never left comments, and 2, make users that post a lot and have been members for a long time ‘premium subscribers’ and offer them additional content.

Anyone know if there’s something like that? Otherwise I have to dig into my database continually.

Thanks!