I have tested more portable MIDI controllers than I can keep track of, and I will tell you right now: 37 keys is the ideal size. While Arturia's 25-key MiniLab MK3 is a solid controller that easily fits in a backpack, it feels a bit claustrophobic. The new $149 MiniLab 37 adds another octave, giving you much more room to play bass and lead simultaneously, or just play more expansive chords. Physically, the MiniLab 37 isn't very different from its smaller sibling. It's got the same solid (if slig