I guess this could have been answered even faster in the MP dedicated topic
My personnal feelings about it :
-I'm a proggy guy and albums from TOT to BC&SL were harder and harder to enjoy as much as everything before them. So I guess something in the writing process / style changed.
-I prefer MP's drumkit sound and recording, it feels like Mangini's cymbals etc are in another room, the bass drums sounds like war dakka dakka typewriter thing and the only thing you hear over it is the snare, that hasn't lot of taste. I wanna hear Mangini with a prog drumkit, loud cymbals and a snare that has some color.
I mean, that's why people say it sounds robotic and "less good" than MP, that's a drumkit sound I would use on a fear factory tribute, not yes/rush fans playing prog music.
-MM is totally capable to play groovy, after or before the beat etc, being someone else and the band wanting to go forward doesn't mean they must forbid themselves from composing an I&W or awake vibe !
I would not say metal happened late in the band, the mirror/lie etc are pretty heavy straightforward songs !
So I'm a little torn, I love what MP did, I think the change happened at the right time for the sake of the band, I even think that MM is a good fit, but I wish they could think a little about what we like and always liked, that is a little off.
Now, onto JLB vocals evolution