Call them before the other guys!
I had another company come in and assess my A/C after the motor died on the outside unit. Didn't know at the time that there was a root cause for that and lets just say $$$ later I found out. The "Other Guys" gave me an estimate to fix the root cause (which was a leaking evaporator coil). O_o Wow!! I had to shop around and Google found me a savior. I called up Champion A/C they had someone out the same day with a free estimate and quoted me half the price of the "Other Guys" (yes you heard right, half). They installed next day early morning all I had to do was show them to the attic and they did the rest, not a peep from the installers. I even got a check-up call from Champion midway through to see how things were going. When they were done... Cool air again.
Special thanks go to Gerald and Larry. Maintain that level of customer service and you will be superstars.