I received a Hornady case prep machine as a gift - the big one with the trimmer on it that operates in a vertical position. I tried it. Far, far too slow for me. Yep, it works ok, but I found it to be cumbersome and slow. I DO use the lower part of the machine that mounts and powers the primer pocket reamers or chamfer bits, etc.
For case trimming, I use a Trim-It 2 like ponchh above, or if I'm doing a small number of cases, an L.E.Wilson trimmer which is simply the best (and simplest) there is. There you have it. My two cents and the advice is worth exactly what you paid for it!