Decades ago we had case trim dies which were fast to use excellent in repeatability when the user kept his shell holders clean. Then other brands began to offer the hand cranked lathes. That's a bit sad because the trim dies were (IMHO) all that most of us would ever need; there's no way I'd part with the half dozen I still have.
My first crank trimmer was Lyman's original "Universal" with a universal shell holder that works quickly and fine. IF I was careful in my work; nothing works well if the user is sloppy. And added lure to the Universal is the add-on tools for it; I love their military crimp removal cutter, their primer pocket and flash hole uniformers, their chamfer/deburr cutters, their outside neck turner. None of it is anything a competitive Bench Rester would lust for but they all do good case work for what most of us would ever need.
I have used a few other lathe trimmers and liked Wilson's (second) best in spite of it being (IMHO) a bit clumsy and slow to use. I also liked Redding's trimmer because it spins the cases instead of the cutter and that method makes the mouths exactly square with the necks.
Lee's unique trimmer tool is an excellent trimmer and is very fast, it's a great device for anyone trimming a large batch of cases.
I don't have to impress anyone; after some 55+ years, the only case length things still in my bench storage boxes are the old Lyman, a few Lee's and the now ancient trimmer dies.
Thing is, I truly doubt that microscopic differences in case length and mouth squareness, alone, make a measurable difference in anyone's group sizes. Selecting cases for uniformity and good necks, low loaded bullet run-out and well done load development have much bigger influence on groups than case trimmers!