The Martelli rotary cutter really does make a difference & I highly recommend it in addition to the Alto QuiltCut system. The Alto QuiltCut holds your fabric steady while you use a rotary cutter to cut it. It has a built in ruler/measuring system and built in angles to lock your cutting bar into. It's hard to explain. I believe they have a video on their site that explains it much better than I can.
I bought mine to cut up scraps into organized sizes.