THIS - I can't believe there is even a discussion here. Taps and dies are for MAKING threads where they do not yet exists.. thread chasers are for clean up and removing light burs.
Thread chasers are the best. Taps are too sharp and may try to cut new instead of cleaning the old threads. If you brake a chaser it is softer and easier to remove. A tap? Not so much. Use the proper tool for the job. Toolmanmike