I've got a Physis H1 and K4 master controller in my home studio. I've also played the H-2 and the V100 vertical. I've been consulting on the project for about a year now. I also have a Kurzweil PC3K, Kurzweil MPS20, Steinway Acoustic (Model "O") and recently started getting into the Ravenscroft plugin.
I'm around digital keyboards all the time -and really enjoy taking them for test drives! I really like the actions and response in the Kawai models (loved the VPC1 with Ravenscroft plugin I tried at the Summer NAMM show). I'm not a huge fan of the Roland sound, but like some of the key actions (RD series in particular). Yamaha has some great stuff, but they also have some low-quality stuff too which they're building to compete with Casio. Not bad stuff, just not the types of boards I'd like to play every day. I really like the AvantGrand pianos - incredible response and "feel" thanks to those little transducers they put under the keys - very cool. Kurzweil has made some great progress and I REALLY like the new samples in the Forte workstation (also available in the Artis).
Just trying to give you some background so you can understand my feedback.
If you're into a true "piano" sense key action, the H1 is better than the other portable Physis models. It uses a modified Fatar TP-400 wooden action with 3 sensors and ivory-sense key tops. Personally, I really enjoy the feel of this keyboard. It's along the lines of the Kawai home-digital and MP11 style actions.
The Physis H2 has a slightly different feel since it doesn't have the wood core or ivory-sense key tops. If you're doing more synth and organ playing - or looking for more master-controller features, the K4 and K5 models are a better solution.
You can checkout this recent review from a third-party source: http://www.pianobuyer.com/fall14/134.html
I think the reviewer did a fair and thorough review of the basic physical modeling sound quality and expression.
It's still such a new product so there aren't a lot of folks who have "under the fingers" experience.
Oh, Myron McKinley (keyboardist/producer for Earth Wind and Fire) is using a Physis H1 - you may be able to find some more info about his experiences. There are some others over in Europe that I don't know much about.
Hope this helps!