Hi Rafal,
the Popp and the Devolo valves are both re-branded Danfoss devices. The Devolo has the additional function to report the current temperature (maybe also the Popp device, don’t know about that). Good-looking? Well, for me there’s only one good looking device: Danfoss (or the OEMs).
The Danfoss LC-13 is used quite often here (I’m using three of them). Working good. In case, you didn’t already knew: You can see which devices are supported, if you take a look at the database for the zwave-binding:
http://www.cd-jackson.com/index.php/zwave/zwave-device-database/zwave-device-list
Danfoss LC-13 (of course) is supported, also Devolo (listed under Danfoss). It seems that Popp isn’t supported at the moment. But this can easily be done. And yes, sadly the Danfoss LC-13 can’t be queried.
I’ve also seen people talking about the StellaZ and the Comet here. But they seem to be a little tricky to handle. And personally, I don’t think they are looking nice. 
Regarding the wall-mounted control: Yes, I am using it. But again: This is originally a Danfoss device. ("Danfoss RS room sensor). And this is what I use. I don’t think that the Devolo OEM is already supported. I’ve integrated it to be exactly what you said: A user interface. A couple of rules and you are ready to go.