Buying a good compressor is maybe the most important thing you need to do besides making sure you service everything well. I went through a 4 year saga with our '90 Deville. Cadillac A/C systems are VERY touchy.
I was stupid, tried to save a few bucks, and replaced my leaking compressor with a reman one from Autozone. I wouldn't even buy a new one from a cheapo parts store unless you know what company makes the unit. Ready-Aire made the reman one that I got, whose clutch failed prematurely and melted the bearing and shaft seal when it overheated.
I found a good parts store that could get me a new Four Seasons compressor, and the thing has been running great since. It cost moderately more money than a reman unit, but it is built so much better.
I also tried the junkyard route. Always a fail with compressors. A/C systems are the first thing people let go and don't maintain on their cars.