I ordered one and picked it up from Lowes a few hours ago. I vacuumed out my car (dry) and it seemed to be pretty good. It definitely has plenty of suction.
It comes with a few accessories, but no brush head for agitating the dirt while using it, so I might pick one of those up next time I'm in Lowes.
I'm not a pro so I can't say whether or not it would be appropriate for people that would need to use it every day, but for a weekend warrior like me I'd say it was a pretty good deal. For $30 you can't go wrong. If you don't like it then I'm sure you won't have any problem recouping your money on craigslist.
barry