I'm sure the Rotratrim would be fantastic. But I'm definitely in the "poor man's" category of printmakers. My solution to print trimming is a glass table top on my 4x8 foot work table, a box cutter, and 100 blade box of utility blades purchased at the local hardware store. The glass table top was about $100, and covers the whole work surface. I throw away the utility blades the moment they start to show any dullness which occurs gradually after several large print trimmings, but they are pennies apiece. These blades cut paper and canvas adeptly, but do not scratch the glass. I let the printer print my cut lines, and I just use a simple aluminum straight edge easily laid down along the cut lines, also purchased at the hardware store for just a few dollars. Sure, I'd still like a Rotratrim, but probably only one for cutting smaller prints (i.e., 16x20 inch or less) which can be quickly rotated on the cutting surface. When working with big prints, I've gotten really fast at walking around my glass table top, thus not having to turn the print around at all as one would have to do with a rotary cutter. My method would undoubtedly never be used in a high-end printing studio, but it works quite well, actually.
cheers,
Mark
http://www.aardenburg-imaging.com