First off, let me say that I've only lived in Phoenix for two years and one of my biggest struggles has been finding good contractors to do work on my home.
I was lucky enough to stumble across Phil's Home Maintenance courtesy of one of their employees. Phil's recommended Miguel at Flores Air Conditioning and Heating and send all a/c related issues to them.
Miguel is very up-front and easy to work with. He charges a flat fee for a service call (in my case it was $90) and then additional charges for any supplies or parts that are necessary. He has a big truck like the other guys that contains lots of parts and supplies so he can do lots of jobs on-site.
One thing everyone in the valley should know about the "big guys" that do a/c work is that the person that comes to your door is paid on commission. This means it's in his/her best interest to get you to sign the biggest possible invoice possible. I am not saying that they all do this, but Miguel doesn't operate in this fashion at all.
I highly recommend Miguel and Flores Air conditioning and heating.
Fully licensed, bonded, and insured. Serves almost all the valley.
ROC 198122 C39R
ROC 198123 L39