Peter at Fireplace Concepts was great (as was his brother, who also worked on the installation). We have a 100+-year-old home that once had a fireplace. It had been blocked off. We removed the wall and hired a mason, thinking we could put in a wood fireplace ... it was not to be, owing to all sorts of issues. Plan B was to install a gas fireplace, and that's where Fireplace Concepts came in (they had done our neighbours' fireplace, too).
While there were many challenges, they eventually made it work, and they did a beautiful job. We love our fireplace. Moreover, they did it to the original deadline, despite all the challenges (which were not owing to them), which meant we had it for Christmas. Would use them again in a heartbeat.