My experience is based on straight wall brass for handguns. My desire was for consistent length so a roll crimp would always hit the same place on my boolits. I do not trim my brass for my taper crimped auto loads.
I started with the basic Lee trimmers and their Zip Trim with the three jaw chuck. That worked reasonably well for the limited cost involved. However, the lengths varied enough to cause problems with a consistent roll crimp. Next I moved up to a Redding 2400 Match Precision Case Trimmer. My decision was based on perceived quality and the manufacturer's marketing info. The lengths were a little more consistent, but they still varied enough to cause problems with roll crimps. My son-in-law uses another brand with a collet style case holder and has the same problem with inconsistent lengths. So much for the old theory that you get what you pay for. The great difference in price really didn't make much difference in the end result.
After a few months with the Redding, I gave up and purchased a Sinclair/Wilson trimmer with their Q-style shell holder. Now I can trim my .357 brass to a consistent length. As usual, my education was not free. I hope someone can learn from my experience instead of shelling out money to learn.