I had a problem with my old furnace, where it was simply blowing cold air. Dean from Furnace Repair was able to come by and diagnose the problem and ordered the part the same day, which was something that was greatly appreciated given the bitter cold winter that we've been having.
The following day he brought the limit switch and promptly got our furnace back in order. He also tuned and cleaned the furnace.
He was polite, worked cleanly and was very prompt accommodating and reasonably priced. He seemed fair and didn't try to sell us on any additional stuff. Having our furnace up and running the following day was a great plus for us.
Other companies quoted us to 3-5 days until they would be able to diagnose and do return with required parts.