Melodyne is an unbelievably powerfull tool. It has its own idiosyncracies, though.
First of all it's important to know that it works only on monophonic (in the sense of "no harmonies", not opposed to "stereo") or unpitched rhythmical sounds. They have to be normalized for best results, and free of reverb-trails.
The more the signal contains "noise", like strong breathing or bow noises, or "sss", "sshhh" and the like, the more it will be necessary to edit the definition file - this is done in the "red" edit window, not the "blue" one where you actually work on your arrangement.
The "simplified" graphics are actually very clever, as you see actual pitch, harmonic center and volume of a note at a glance. You just have to get used to it. The only real fallback is that you have no true information about the actual length and start-/end-insets of your audio file like in ordinary DAWs.
Pitch-shifting and time-manipulation is artefact-free in an almost ridiculous range. You can go up and down at least a fifth without sounding bad. Just in case, you can always shift the formants independently from the pitch, and/or move the rhythmical emphasis of a note without changing its position.
An important detail is to discern between the two pitch-manipulating tools: one actually "flattens" or "heighthens" the pitch envelope (like a vibrato), the second one is very usefull when you want to keep the typical aspects of the performance, but want to bend the note towards the ideal pitch only.
In rare cases (or with voices) it is a good habit to leave certain parts of a signal untouched by cutting it in even smaller parts; "sss" and "ttt" are syllables i always avoid to change. - The good thing is that you can do very clever de-essing too, this way. The bad thing is that these additional cuts will change the score-display (which is not a problem in most cases).
Performance-wise, you gain a lot comfort by adding your own short-cuts after you got used to the basic steps, especially on a Mac, as you will miss the right-click menues. Stabiliy used to be better on PC (funny enough, as Melodyne was developped on the Mac-platform), but it is at least as good now on OSX since Version 2.6.
While Melodyne sports direct integration in most DAWs via the MelodyneBridge or at least ReWire, I tend to see it as a specialized stand-alone utility. I import the files in question (sometimes with a simple rough-mix of a playback) and export the manipulated audio back to my DAW.
... there's too much to tell in a short forum-message. Melodyne comes with a nice manual and a "Guided Tour" when you install it the first time. Take the time to look at it, there's so much power under the hood to be explored.
Enjoy!
HTH,
/Dietz - Vienna Symphonic Library
(edited due to typos)
