I had my Condenser replaced last summer (May or June 2013). Symptoms were, whining sound when the AC was on full blast and warm air blowing.

The low whining sound meant low refrigerant, (confirmed with a quick pressure test). The tech added dye and refrigerant to the system and a week later when the system was blowing hot air again, he check it out and saw a leak at the bottom right of the condenser when you are looking in front of the car.

I think it cost me $6-700 to replace the condenser with an aftermarket Condenser. I think labor was $300 and the part was $3-400.

If the evaporator is bad or leaking, the whole front dash needs to be removed, ~$2,000 to repair.

My condenser replacement lasted until December 2013 and now I think something else is wrong with the AC system. It's hard for me to confirm now since it's been single digits but I think I'm selling this car and getting and MDX.