The trimmer that will give you the best, most consistent, most concentric, results, is made by Wilson... Check out
www.sinclairintl.com...
It's fairly fast to use, and easy on the hands... You can cheaply hook a power screwdriver up to it should you so desire (I haven't found the need, and I'll trim several hundred at a time).
I've also got the Lee trimmers (pretty nice for what they are), and a Lyman drill-press trimmer that I'm going to set up for doing .223... real soon now... But the Wilson works GREAT.
It won't also serve as a neck turner, and all the other "fancy" stuff, but it works, and it is pretty darn cost effective.