MM is a brilliant game.
If you're into sidequests and character development, MM is the game for you. Though it's not a long game, it definitely makes up with content. The atmosphere is more morbid and, I think, not as epic as
OoT, but you end up learning all the bits and pieces, times and places, and peoples' lives thanks to the time system. Musically, I didn't find it all that impressive (I've always loved the music in
LoZ games, but wasn't terribly moved by that in MM), though there are lovely details about the graphics are worth looking at, if you're into that kinda thing. One of the things I love most about MM is how much you change the lives of those in Termina which made, for me at least, an ending that was satisfactory.
As for difficulty, I honestly didn't find it that difficult. Sure, the time/saving system might take a bit to get your head around, but all in all it wasn't too bad. It's harder than
OoT, but nothing I found super hard. Mind you, my younger sister thought it was quite difficult, but I think that has more to do with how long we've both been gaming for and being the old bat that I am, I've had a lot more experience.
All
OoT comparisons aside, it's a fantastic buy and totally worth getting, though I honestly don't think it's for all
LoZ fans. I've heard newbies complain it was too hard and oldies say it was way too different from the rest of the series. Though I'm an older fan, I thoroughly enjoyed it. Doesn't hurt to give it a go, so go on and try it out (: