This may sound crazy but we have been using a tool we purchased at Sears a decade ago. It is a snipper that uses a razor blade. The blades can be easily changed out when dull. We bought a bunch of blades at the time of purchase
Ours is a much older version and looks a bit different but all in all very close. It cuts thru 3/4" line like butter. We first tape the line with masking tape, cut thru the middle of tape then using a small butane torch melt the end. Finally pulling off the remaining tape.
We have been very pleased with the tool and also use it for cutting nonwire hose
Good luck with your choice.