As someone who appreciates simplicity, I've used the Lee trimming system (cutter with interchangeable stud that controls case length-if they also make a better system now, quit reading) for decades. However, you can't really depend upon the accuracy of the trim and since Lee does regular steel cutters, they get dull with much use. It can also be most time consuming even with an electric drill/screwdriver rotating the cases.

If you are going to go this route, have a good calipher on hand and check the length of each and every case while trimming.