Avoid
We had a visit from Top Quality in February to adjust our HVAC unit vent to control the airflow between the two floors of our home and change the filter, and we talked about setting up a yearly plan to do this every spring and fall (this is routine maintenance we do every year). Everything was and had been working fine at that point.
About a couple of months later, the unit stopped cooling, completely. We called them back out and all of a sudden the coolant was 100% empty. We were told that there were "king valves" broken and a leak somewhere, but their tech could not find it. We were given quotes for thousands, up to over $12,000.00, really pressing for a whole system replacement and zone addition. They did offer a repair but that was conditional upon "we might still find something else." No further attempt to try to find the leak they insisted we had, and they charged us $330.00 for nothing at best and sabotage at worst (details below).
We decided to get some other opinions, who told us these same things...that there were a couple of the "king valves"/o-rings missing on the outdoor unit (I put king valves in quotes because they said they never hear anyone refer to them that way anymore and it's possibly to confuse clients if they go a-googling, and also that they can be bought by the dozens/hundreds for a few dollars). Additionally, they found all of the seals/gaskets on the outdoor unit were loose, and said that there was a large amount of debris on it that suggested a very large, very fast coolant spray/leak. One of them also said that Top Quality's guy did not even check the coil in the attic because some sort of original seal was still on the cover/door.
They all claimed to have the newest, most expensive leak detectors and could not detect any leaks anywhere. They agreed (all of this independently of each other) that if there was a leak, it was so small as to be undetectable and not a problem. I did look back through my old records (I keep everything) and saw that we last had a coolant refill about 7 years ago, and the diagnosis was the same. A possible small leak but not a problem yet. One of the alternate opinion companies this time did a two day and overnight test where he put something in the unit to see if it would leak out. It held 100%. He filled the unit with coolant, fixed the valves and seals, and it has been working just fine again since at a TINY fraction of the cost Top Quality wanted.
Now these are not my words but those of the other opinions. That the tech from Top Quality didn't know what he was doing, to run away as fast as possible, and that it even reminded them of situations they had heard of where techs had drained a system of its coolant to re-sell it. It does seem strange that a simple filter change and vent adjustment turned into an empty unit within a couple of months (or sooner, as we had not been using it much yet because it wasn't hot enough, so we wouldn't have known until later), with no leak able to be found by anyone, and a unit working just fine now for several months with just a coolant refill.