Phenomenal. The guys were nice and respectful. We ended up discovering a leak in the HVAC system and needed emergency service at the same time they were here. They went out of their way to take a short break so we could resolve the issue.
During the estimation process, we appreciated that the estimator admitted that only one of the systems really needed the service. It showed that they have some integrity.
The only item for improvement, and this is very minor, is that they could maybe vacuum the entryway and stairwell after getting done. We had to do a fair bit of cleaning after they left.