Yes I use it. It is based on presets, but you do work with layers. I'm just a hobbiest, not a pro. I use it mainly for stylizing, finishing off some images. It's "content aware" capability through the use of masking is great. I've not spent much time with the portraiture, B&W, or Resize.
It does integrate well with both PS and LR. It also uses Smart Photo, which is very much like PS Smart Objects. For example, you have images imported into LR, do your basic editing, then want to add something more in OnOne You can send it to PPS Layers, it asks if you want to use Smart Photo, checking it allows you to open that image back in PPS anytime later and the edits you done are preserved.
The current version is 9.5, and just a heads-up, they're preparing to launch the next one in October. They're changing the name somewhat, from Perfect Photo Suite, to OnOne Photo 10.