I have a 24 inch Rotatrim dual rail that I bought on Ebay a few years ago and find it absolutely great. One caveat to consider however is the size paper you are going to cut. When I bought it I was using 13" roll paper. Now I have a 3880 and thus 17". No problem. however I recently acquired a 24 inch roll of paper and thought that would be no problem as I would cut into 17" strips giving me neat 17 x 24 work pieces.
Wrong. the 24 inch cutter was at it's absolute and could not get the 24" inch edge under the wheel. I think they also make a 26 inch unit. For my needs I now cut with a metal straight edge and a sharp utility knife on my wife's sewing cut mat.
Martin