Used Ditra Heat-E for the first time last week. Tiling 600x600x15mm limestone onto old wooden floorboards, in a small bathroom 1.8 sq m floor area, using 1.6 sq m cable kit.
First bonus was the provision of a form of Ditra mat to lay cable onto - Schluter said it was ok to (fully secure floor boards first) prime, 6mm spread of rsf, mat, cable and
tile straight on top.
It is incredibly convenient way of installing ufh, but also very expensive (twice the expected price - good old Schluter, reassuringly expensive). I would personally recommend it for even DIY installation it is so easy, you can install the cables extremely accurately as quick as matting, and no self leveller needed.
Finally, I got caught out by the high resistance reading of the small length of cable - over 200 ohms, it went off scale of my resistance meter, and I thought cable was defective (oops). Discovered my mistake after a few phone calls.