What bothers me most about MM is how he can never answer a question without going into an overly long, drawn-out reply. A lot of times when they ask him in interviews how he likes being in DT, and touring and all that, instead of answering in a clear-cut, straightforward manner, he proceeds to go off on all these philosophical tangents. He never actually answers the question precisely; he isn't brief and to the point. I always feel like "just answer the damn question like a regular person!" lol. I think it's probably just the way his mind works; everything has an over-the-top mathematical approach. He's very analytical, and probably overthinks a lot. At least, that's what I take away from his interviews.
Having said that, I've never agreed with many others about his playing being robotic, or lacking feel or emotion or whatever - the guy can groove. I also don't perceive him to be just a "metal" drummer, either. His latin-jazz and afro-cuban playing is off the charts. I was fortunate enough to attend one of his clinics back in the day, and he played everything from technical metal to latin-jazz! That's why I was super excited when he joined DT, because I felt he would bring all kinds of sick new elements to the band - kinda how when JR joined, it took the band to a whole new level of musical possibilities.
For me, that has yet to happen with MM. Of course, that isn't necessarily his fault. As has been discussed lately, he might not be given the kind of creative input he'd like to have, so who knows. I do think the albums he's been featured on do have a lot of "Mangini-isms" in them, but stylistically I don't think he has really offered anything new or groundbreaking. Their music since MP's departure still sounds relatively the same, and I was hoping MM would take the band to a whole new level, and challenge the others rhythmically, much like JR did when he joined. I get they want to stick to their identity, for business sake, and I get that it's a balancing act for Mangini (knowing how and when to add something new, etc), but still. Overall, can't really complain - I love The Astonishing.