I started using s/h about 3 years ago for paphs and phrags solely out of efficiency. It's a modified method in which I punch holes in regular pots and sit a whole bunch of them in shallow "communal" trays of water. It made it easy to water them all at once whenever I had the chance--if the water dried up and I didn't have time to water, I just added more to the bottom until I had the time. Based on all that, it seems that phrag hybrids LOVE the stuff. All the besseae hybrids, all the long-petalled hybrids (i.e. Grande, Nitidissimum) grew tons of roots, often with the tips streaming out the pots and into the trays. I don't grow besseae in s/h not because it didn't root well (it did), but because when it got real hot here in the summer, the roots got too warm and the plants started to suffer. I tried a couple wallisii in it briefly--one did ok, the other hated it, and both have since been moved into a more traditional medium. I tried a baby warscewiczianum in it and it didn't seem to like it. I have since avoided putting any of the long-petalled *species* into it.
Paph-wise, I don't think s/h is a "preferred" medium--personally I think they grew better in a CHC based medium. Overall they seem to do OK. The coryos seem to root well enough into s/h. Most of the Maudiae-types do well too, but I think they kind of resent it when the water reservoir gets colder in the winter. I tried brachys briefly without success. The cool water in the winter seemed to rot the roots in short order. The parvi hybrids seem to be hit or miss--some did really well, some not so well. I suspect that's not grex-dependent, more like plant-dependent. Most paphs do well in s/h for me but there are a few that just go south in short order, and I still don't know why.
One more thing--I tried to put some marginally-rooted plants in s/h. I couldn't have killed them faster if I had mounted them on cork.