Anyone use these? Not much in the review section. We currently have a Temco TFC 424 prefab fireplace. Dealer I am currently working with says that although some inserts are approved for prefab, the prefab manufacturers don't approve inserts so he won't install them. He is recommending the Appalachian Gemini zero clearance wood stove to replace my fireplace, which means tearing out the existing fireplace, stone surround, etc.. Opinions?