Rebuild or reman trans

Hey guys I have a 2000 Chevy k3500 with a GMC 4l80E. Have all forward gears and no reverse. Tried the servo pin extension and the reverse worked again for awhile but won’t anymore. I have to bite the bullet and get it fixed. Is it better to get a new/reman transmission, or just get the old one rebuilt with warranty. Anything helps. Thanks!