It depends on what I am trimming really. I have a couple of the World's Finest Trimmers for 300 blackout and 223. I can hold +/- .002" with the WFT. They are easy to use, but do require the brass to be sized before trimming.
This +1 or I've been using a Lyman universal case trimmer that I bought the adapter to run off a drill and it works really well but the speed of a WFT is worth the money. I guess it would depend on how many different calibers you reload for.