I used to sell rotary cutters, stationary and hand held. Dahle, Myers Precision Cut, Friskars and Carl.
Far and away the best quality was the Myers from England. Pricey, but darn well worth it. Dealer discount was low so don't expect any great deals...Available from good art material stores through Alvin & Co. an importer and distributor...probably only by special order.
Dahle is a German brand and they make excellent cutters off all types, but I wasn't thrilled with the performance of their large (about 40") rotary cutters. Smaller sizes were fine.
Best value...Carl Cutters out of Chicago. Inexpensive and good quality for everyday paper cutting for the price. I actually have about 5 or six of the Carl cutters still on hand in their boxes and would be willing to make a good price to any Grumbler wanting one. I don't have them in front of me now, but I think I have two sizes on hand...about 18" and 24" and extra blades too. I wouldn't recommend cutting matboard with these though as they aren't as heavy duty as Myers or Dahle. Dahle shouldn't be used daily for cutting board either, but the Myers is a tank.
If interested in a Carl, email me. With shipping should be less than $ 100.00.
Friskars makes some small rotary cutters that are fine for trimming photos, etc. You can pick these up at any good craft store.
You can cut mat board, acetate/mylar, tissue, vinyl, paper, fabric, thin metal, and almost any other thin material very precisely with a good rotary trimmer. Razor thin trimming too.
Dave Makielski