We just had ours installed in our MB, and will be having it installed in our hall bath shortly. Because it was already warm weather here when ours was finally installed/hooked up to the switch, we haven't really programmed or used ours yet (turned it on the first day just to make sure it worked though--it does!).

Our tile guy had recommended Nu-Heat because it comes on/in a fabric type mat, which makes installation easy (easier than some of the other types I guess). DH liked what he'd read about it, and liked their tech supposrt when he called with questions. He also felt more comfortable using a product that our tile guy was familiar with and liked installing.

These two bathrooms aren't on slab. Our tile guy poured a 1" thick mud base over the plywood subfloor. When that had hardened--next day?--they covered that with a thin layer of thinset, then the Nu-Heat mat, and coated it with another thin layer of thinset. Next day tile was installed over that with normal am't of thinset (for tile installation).