Disclaimer: I make this software myself.
I recommend MIDI Designer. It has many advantages over all the other offerings out there, but the best one is: a free Lite version that really does EVERYTHING the Pro version does. It's got two limits (no more than 12 controls and no "colors" for background pages), but aside from that it's the real thing, so you can try before you buy. I cannot imagine not giving users this choice.
I made it for my own music making (I use Ableton Live, mostly) and for my band (we use hardware on some rigs, hardware and Reaper on others, and hardware and Cubase on others). This doesn't mean it's got to be good, but it means it's got to be performant.
Also, the developer -- me -- is directly available, not just to answer questions, but also to respond to feedback about the app. 70% of the features I've added recently (about to show up when 1.03 drops) is directly culled from user feedback (and direct interaction with my user-testers).
But again, try the Lite version for $0 and see what you think.