When we bought our first house, the home inspector had some concerns regarding a leak in the HVAC system in the basement. We found Burkee Climate Control, and they worked with us to have it checked out before our closing.
When I made the initial call, I was pleasantly surprised to have someone actually answer the phone, rather than getting an answering machine. They asked some basic questions about the system and the problems that were found, and explained what their initial thoughts were. When I told them that we were closing on the house soon, they worked with us to schedule and appointment quickly.
The arrived at the house when they said they would, which helped us out since we had to have our realtor arrange for them to have access to the house (since it wasn't ours yet). They looked at the system, and again said what they were initially thinking it might be. The technician also explained what he was going to do, and what he would look for.
As he was going through the system, he didn't mind that I was watching over his shoulder. In fact, after he learned that I was going to be a first time homeowner, he took some extra time to explain how much of the system works. He had told us what he was looking for earlier, but he then explained how certain things he was looking for might affect the performance of the system.
Luckily, there were no major problems found with anything, but he provided some suggestions for things to look out for. He also performed some basic maintenance on the system as a courtesy.
Overall, the service they provided was timely, quick, and very informative. I found it nice that he didn't mind me watching what he was doing and asking questions about it.