I have been playing with ML for a couple of years now, but usually the stuff they have is just slightly too inconvenient / too slow to enable to make these features truly useful in real life shooting. I played with things like HDR, focus stacking, Samyang 8mm Livew View defishing etc.
The first truly useful (for me) feature - dot-tune lens calibration - was introduced recently, and works really well.
Another very promising feature - full HD video recording enabled in my camera (50D) - is still not very interesting, unless they implement some way to sync the video with an external audio recorder (I purchased Zoom H1 recorder specifically for this purpose). It could be as simple as letting the camera beep every time you start video recording (so it'd be easy to sync video and audio in PP). Not clear if ML will implement this though. The developers are obsessed right now with RAW video recording on 50D, trying to get to full HD RAW at 24p. But who needs RAW video if it is too cumbersome to sync audio with video? (Basically, you always need an assistant with a clapboard.)
Once I get my first tablet with USB OTG capability (meaning I can use it as an external Live View monitor) - it is on its way - I will probably like a lot the "ghost image" feature of ML, for my photoshopped photos (levitation etc.). This will allow me to compose a sequence of photos very precisely, by being able to display an older shot in LivewView (half-transparent), while composing the next one.
You should definitely at least give ML a try - there are so many features, you might find one or more very useful in your work.