Am installing a porcelain tiled floor - onto an existing concrete
subfloor. I have decided (after reading the thousands of messages on
the subject!) to install electric underfloor heating mats (on top of
insulation boards). I am well aware of the
economics/advantages/disadvantages particularly in comparison with
water systems. It is a playroom with central heating and the idea is
only to take the edge off the cold tiles.

There are so many different products/suppliers - Devi, WarmUp,
SpeedHeat, Wickes etc etc. Does anyone have comments on good/bad
experiences with individual products?

I am intrigued by a product from Rayotec which appears to use cable
much closer together thereby making the product thinner, and able to
operate at a lower temperature. Any experience of this?