I have two split heat pump/electric heat systems. If the systems are still efficient, and you don't feel like breaking the bank, I'd replace the motor. After all, the entire system is just a bunch of pipes, so the condenser motor is one of the few moving parts. We had extremely old systems that we kept patching and patching. I think we got an extra five years out of the units, without costing us a fortune. Now, once my son came, I was done playing around so we got everything replaced, but I had reached my breaking point at that time! By the way, consider that our "new" units are now five years old and they've already paid for themselves about 2x over in energy savings in comparison to the old units.
If you can get away with swapping out the motor, go for it. However, when its time to replace the units, don't hesitate because you'll get a good return on your investment.