One ac company says bad evaporator, one says bad compressor. Unit has always performed well. I made sure coil;s are clean ? Seems hard to trust anyone on the repair.

What kind of refrigerant is in this AC unit? Without knowing that I cannot tell you anything. Also, describe the unit.

One note: Units freeze up due to reduced load on coils because of poor air flow. A dirty blower wheel will cause it to freeze up, too. Also, check the underside of the coil; it may look clean from one side, but it's really stopped up. Have you cleaned it with foaming alkali coil cleaner? If not it could be full of dirt between the fins that you cannot see. I have cleaned many, many coils that looked clean, but they were stopped up. Either the coils or the blower is dirty or the fan is on a low speed.