I’m very pleased with my MTH K4S now Chuck Sartor has had it, but I wouldn’t look at another PS1 locomotive unless it was VERY cheap...
Williams brass or MTH Premier PS1 Challenger are about the same price. The MTH version has a more robust driveline. If the PS1 unit is bad swap in a reverse unit and be on your way for conventional running.
I run all command, so either one would have the electronics replaced.