We have been using the Kerdi-Drain/HydroBan combo as a staple in our shower pan construction, but I am thinking of going back to Kerdi. For the shower walls, you can't best the HydroBan, but over top of the sand mix in the pan, it often proves to leave us with a surface that is more fragile than I would like. The Kerdi gives a more durable surface, for the occasions where you(or anyone else) will be working on top of the shower pan before the mosaics go in. A piece of plywood, or cardboard, or something helps, but I've seen the HydroBan damaged and have had to touch it up many times.

Aside from that, we've had great success with HydroBan. We're actually in the midst of a swimming pool and whirlpool tub project. It's all HydroBan under 1"x1" glass mosaics. The hardest part has been making the general contractor understand just what exactly the words warm and dry mean.