The first thing that bothered me was once installed, it took a long time (about +12hours) for the floor to start to feel heated. Since it took a long time, I didn't want to turn it off, so I leave it set at 80 degrees all day long to feel some warmth (I would increase it, but it says 82 degrees is the max to set it). Another thing that I wished could be better was the temperature of the floor. We used a self leveler and our subfloor is concrete, so maybe that affected it, but I don't feel the heat strong enough. The thermostat look and settings is really nice and the shipping was fast, so that was good.
Absolutely. We've heard similar customer feedback with cold concrete floors and have decided to start carrying insulation. We now advise all our customers with concrete slabs to add cork insulation.