They had the installation done in a little over a week and the city inspection completed two weeks later - WELL BEFORE the Dec 31 tax credit cut-off. This is something three other installers I talked to said couldn't be done based on the permitting process alone.
As a retired electrical engineer and home owner I carefully monitored the workers during the installation and the finished product. The workers were very friendly and did not appear to be bothered by my monitoring them. I could not be more pleased with the quality and care of the installation.