I think the ONLY wrong choice is to keep it and get $50 AND lose the warranty. No one competent will repair it for you for that kind of amount.
I'd choose between refund and repair.
My choice will probably be to put a film in it and do a test run to see if there is anything else that needs attention such as view finder calibration, film spacing, light leaks, etc. Then if too many things are wrong with it, ask for refund. Or, if shutter is the only thing, get it fixed.