I have been using a paper cutter to cut bands for years. Works great. I tried the pizza cutter thing, works ok but I went back to the paper cutter. The paper cutter works best when a shelf (outside the blade) is used to hold up the band.
I got one in Lidl that had a guillotine cutter and a roller cutter. Now perhaps I was using it incorrectly but I found the guillotine would only cleanly cut rubber that was placed close to the hinge point. I ended up throwing it out as it was taking up room and hadn't cost much.
I have a Ingento 15 inch Maple base model. It's a good one. For me there is nothing better to cut bands with. I measure,put a steel ruler on the rubber,keep it as close to the blade as possible,press down a little,make the cut. Nothing will give you a straighter cut. I keep an Arkansas stone handy and just wet it and go up and down the edge once and awhile(1 or 2 strokes only) to keep any burrs off.I don't like Rotary cutters. On long cuts the rubber moves and the cut isn't the straightest. Don't get a cheap stamped out metal guillotine cutter. Get a good heavy one made from Maple or good metal. I've been using one for years. Flaband