As long as you got what you paid for it was priced right...I hate contractors that intentionally low ball crap then grind it up through change orders and begging.
I dislike even more the foolish consumers who think that three estimates that range in price are for the same product.
Each and every estimate only reflects what is in the minds eye of the builder providing the estimate. That is why even if your staring at 3 identical prices, each of those bids has absolutly nothing to do with the other...
The only thing you can do is look at the guys work, and talk to his previous clients.
I got undercut buy a guy who came in 250k less then me on a large remodel[my price was just under 750k]. The next guy was 150k over me. The customers took the low ball, and the job cost nearly twice my bid, and took twice as long as I had projected. Live and learn.