I purchased one recently and I have been really pleased with it. I think this controller is slept on.
The size is perfect, giving enough room for keys and kk=nobs AND a screen which is what sets it apart from many sort of similar controllers. I use it with Ableton and the integration is really nice. It does the Blue Hand thing perfectly, and has a read out on the screen for device banks (but not the individual parameters, unfortunately).
I coincidentally tried to out last night with my iPad Pro, specifically Drambo, and it was a good/solid controller. The sequencer is only integrated with Personus Studio, which is a shame. It can be configured from the device itself, unlike MANY controllers out there, which makes it really flexible.
The keys can do Velocity, Aftertouch, AND/OR Poly Pressure, the latter which works REALLY well with instruments Ableton.
Let me know if you have any specific questions.