Oliver Chesler has an interesting look at the Audio to MIDI feature in Live 9. He compares it to Melodyne, actually:
Whatever you think of the results as much as I love Melodyne and use it it’s not a feature built into Live therefor one step away from instant. I also don’t think you can Audio to Drums like you can in Live. The real killer feature for Audio to Midi is my own whistling or humming to create parts and ideas.
Of course, it can’t affect the audio signal with the MIDI analysis like Melodyne can, so it seems more of a songwriting tool to me. Either way, he made a cool video demonstrating the difference between the two:
Via Wire to the Ear.