Some info here on what I use and why
I use a Wilson trimmer, have previously used the lee and lyman systems but after using one of these belonging to Apollo I bought my own. This unit seems expensive but it costs the same as my lee and lyman lathe units combined which are no longer used. Buy once, cry once I guess.
The main reason for using it is flexibility. You buy a case holder for each family if cases, .222, .223 or .243, 7-08, .308 etc and just tap it onto the nylon pad to secure the case, tap to remove.
Then place the case holder in the trimmer and turn the handle. There are power drill adapters available.
The unit can be used to square the case head, careful not to remove too much metal, usually one or two turns is enough
In the pic you can see how even the best brass can be out if square.
Then you can spin the case around and trim to length. This model has micrometer adjustment so you can measure your case and dial in the length.
Hope that is of interest to some
Chronos