Personally, I would rather see the workpiece firmly stuck, than moving around whilst you are cutting. For acrylic, I use fabric embedded carpet tape on a sacrificial bed of plywood and get the piece off afterwards by sliding an artists palette knife underneath. The tape then either comes off the bed or the workpiece (sometimes both) and because of the fabric reinforcement, can be pulled off, with a little cleaning up any residues with low-odour white spirit.