as i acquired ableton live a while ago i became interested in max 4 live as a possible alternative to pd.
i'm quite happy with pd, don't get me wrong, but as i mostly work with sample buffers, some of the pd-extended's problems with GUI vs. sound engine can be a problem (so far i've managed to work around them, thought)
so i tried the M4L-demo and immediately the excitement started to fade. the "stereo in/stereo out and that's all folks"-limitation for max-app was the first drawback as i've just started to play with surround sound. i know it's possible to run multiple max-apps on different channels and achieve surround that way but i couldn't find information whatever it's possible to share audio btw max-apps. propably not. actually, i couldn't even solve whatever it's possible to run audio AND midi to one max-app as there's a separate instrument for audio and midi channels.
so it seems M4L is more intended to be an audio/midi instrument/effect with emphasis on using the live side than the other way around.
i really could make use of some max/msp:s advanced sample buffers and gui-candy but otherwise the change from pd -> M4L seemed to introduce more problems than solve old ones..
maybe buying the full max/msp? i don't know. 400usd for a couple of extra modules is not exactly cheap.. and iLok is something i wouldn't like to get into..
so at the time i just continued using pd. it's something that i know my way around and i like this community.