I think it's an amazing ability to improvise - especially if you can do it in more than one key. I don't think those examples (or the ones i listened to) are 'improvisation' in the classic sense - but i'm not a big fan of 'modern' and 'minimalist' music. To hear in improvised guitar, drum, bass or trumpet solo, for me, is one of the best things you can hear. Especially if the musician knows how to really 'work' their instrument. Simon gall is one of the few local musicians that i have really enjoyed watching improvise.