I enjoyed so much of MOS, so it was a success in my eyes. They succeeded in what seemed like their main goal -- making Superman cool again. The film, overall, was very true to the character and the mythos, despite the addition of new Kryptonian elements. This WAS Superman, in spirit and appearance. Cavill nailed it, as did most of the cast. The film has it's weak moments, many of which have already been discussed to death around here, but I definitely think the good out-weighed the bad in the grand scheme of things.
At this rate, we're so used to seeing origin stories that it's getting tiring. There's no way to start a new Superman series without retreading the core elements we've seen before: opening scene on Krypton, growing up with the Kents, developing his powers, learning about himself from Jor-El, etc. The first quarter of MOS was a little awkward and all over the place, but I liked Snyder's spin on things. It was cool to see Clark wandering and unsure of himself, leaving a trail of good deeds in his wake. All little different (and more realistic) than leaving Smallville and donning the suit right away.
My main gripes are the extreme focus on alien tech on earth and the sheer level of destruction. I could see why some critics would roll their eyes at the second half of the film, especially older folks. This is the kind of movie my Dad (early 60s) would hate. There's just so much BING BANG BOOM CGI BOOM BANG SLAM action that it does feel relentless at times, but I ate it up and loved it. There are some really amazing moments and so much impressive action that it's a lot to take in on one viewing. The final Zod/Supes fight is really special, IMO. Totally badass in every way.
As I said, the amount of destruction bothers me, not because I'm upset or uncomfortable about the amount of innocents who must have died, or that it evoked 9/11 imagery. No problem there. It's a sci-fi disaster movie at its core, so that wasn't a problem. My problem is just that nearly all of Metropolis looked like it was leveled. We're talking No Man's Land here. Realistically, it would take decades to bring the city remotely close to what it once was. Even if Superman spent a lot of time helping to rebuild to speed up the process, the amount of money it would cost would be astronomical. Also, what kind of threat is next that tops this one? Near-worldwide destruction? Where do they go from here?
Interestingly, I think the destruction leaves good opportunity for a shining, wealthy public figure like Lex Luthor to step in and offer a helping hand. Lex...or Bruce Wayne.