I used a Forster for years but find the Lee to be the best/quickest.
http://www.midwayusa.com/product/476992/lee-case-trimmer-cutter-and-lock-stud
Add a cartridge specific shell holder/guide and a cordless screwdriver of drill and you're in business.
Just mount the shell holder in drill and a quick twist locks case for power trimming.
I mount my trimmer and a de-burring tool in a wooden handle which allows you to trim and de-burr without changing tools. I find it easier to trim after each firing than to measure and trim only the long ones using this setup.

Regards,
hm