Those stick-type hot wire cutters from the craft store that plug into the wall aren’t much better than a knife. The actual cleaving of foam is easier, but dragging a long, hot flexible wand ...

but for regular wire, I just use a pair of diagonal cutters or a mechanical stripper or a razor blade. You can do that, of course, and for large solid wires, you can even get good results.

and small bolt shears (usually 6/32 and 8/32) for cutting bolts. Standard wire strippers can usually strip wires between ...