I was very impressed with PDQ. My A/C stopped working, I gave them a call, and they were able to come out the same day. Turns out the motor on my unit was broken. They fixed it right away. The bill was much lower than expected!
Edit - I have to lower my rating. The compressor fan motor was replaced quickly, but they left it unbalanced. It is loud and putting undue stress on the unit. When we called them to come fix it a week later they said that this is how it is and wouldn't fix it.