I have used several different "chop" type cutters, including the RP. Of them all, the RP is by far better constructed. All aluminum, has some weight to it, the cutting arm has a great bearing surface so it does not wobble at all, Very nice mitre gauges and a stop. It uses a single edge razor blade, but without the "handle" on one edge like a standard blade. Has an inlaid cutting mat in the cutting area of the table.
Some of the others I had have a rather poor bearing for the cutting arm. One I had to replace the particle board base because the groove where the blade hit it got so big the cut parts splintered on the back.
All that being said, none of the "chop" type cutters cut with a perfectly strait cut end. They all leave a bit of a taper and require sanding to truly square the cut end up, although I think the RP does the best job for me.
I finally bought a mini chop saw or as some call them, a mini power mitre box. Proxxon makes a very nice one, but the price was out of my range. I got the one from harbor freight, with 2 packs of extra blades for about $50.00. It cuts great, with very square cuts. I made an extended base and a fence for it as most of my cuts are strips. Cuts up to 1/2" X 3/8" stock, hard and soft wood. With a cutoff disk it will cut metals as well.
EJ