chris.r
Seamless integration with new mainstream hardware controllers like icon, xtouch, avid, nectar etc should be priority, they are smaller, cheaper, better now. And of course the compatibility with widest selection of audio interfaces. That should give good foundation for a solid studio.
Aren't those controllers pretty seamless anyhow? Anything I've used that uses the Mackie protocol worked pretty much out of the box.
For anything else you can either use ACT, or Alexi's AZ Controller which will work with anything.
I'm using the Mackie MCU/XT/C4, Korg Nano Kontrol (both studio and mini versions), BCF2000 and all of them work fine. In the past I used the Philip Rees C16 and the JLCooper CS32 - I've not checked the latter two with CbB yet, but they worked fine with Sonar so I doubt anything has changed.
And as far as audio interfaces go, if it has drivers for Windows it'll work. CbB supports ASIO, WASAPI, WDM and MME which basically covers all bases.
Is there anything in particular that doesn't work for you?