I bought a Kodak M series which works well for events, but it pales in comparison to the Rotatrim which is the studio's workhorse. If you only need an occasional use trimmer, skimping is okay. Otherwise, I'd go straight for the Rotatrim and not look back.
Good and cheap in this category rarely collide. Dahle and Rotatrim are you choices. Like tripods if you buy a cheap one sooner or later you will realize your mistake and buy a good one. Might as well skip the cheap brands a get a good one to begin with.