It's a long story. Bought a house in a new development in which they were the initial installer of the system. The system came with a five year, parts only, warranty. Within two years, the initial compressor failed. They replaced that under warranty, charging $350 for the labor. The replacement compressor came with a one year warranty (bye-bye, five year warranty). Three years later, the replacement compressor failed. Two months prior to that, the system wasn't cooling, and we called in a third party. The refrigerant was gone, which they recharged. In retrospect, the loss of refrigerant (normally good for 10-15 years) is indicative of a leak in the system. Since the refrigerant is also the lubricant for the compressor, it helps explain two compressor failures.
The first telephone conversation I had with them after the failure was determined included the statement that the compressor was still under warranty. When the service agent was on site, I was apprised that the warranty was for only one year, and that it would cost approximately $1800 for a replacement.
Long story short, the initial installation was flawed, in that a very minor (but major), slow refrigerant leak was introduced.
I'm dismayed on several fronts - first, that they wouldn't honor the original warranty, and secondly, that would charge $192 to verify what I already knew. In my opinion, this is basically a "milk the customer for all he's worth" organization.
My recommendation is to avoid them at all costs. And, by the way, we found a nationwide service that installed a new system, complete with ten year warranty on both parts and labor. The installation was professional and thorough, and the new system is much quieter, even though it was a "builder grade" (i.e., least expensive) unit.