I finished it last week, fastest I've ever completed a game (and I am one of those who rarely finish games). Despite a couple of nights of rage-quitting, my extreme dislike of first person shooters (or third person shooters, or whatever), I soldiered on to the bitter end and then felt completely empty.
Even after sitting through the credits and being rewarded with essentially the "this is all just a story" cutscene, I felt betrayed, lost, confused, depressed, and angry. One review somewhere said that if the game made you feel something, then they've done their job. In this case, I heartily disagree.
From the first moment my Shepard said something that I instantly responded with, "That's not what my Shep would say," I knew I was headed for disappointment. I spent hours and hours with her through ME1 and ME2, and knew which lines felt right in her particular situation. My Shep worked hard to bring people together. My Shep (well, this version anyway) was honorable, decisive, willing to do what it took because she intended to save the galaxy and not just Earth.
Every time I had to choose lines that hinted all she cared about was getting help for Earth, I died a little. My Shep cared about Earth, of course, but she wouldn't have obsessed on it. Getting krogans and tunarians and salarians to do things for the ultimate goal of saving the whole galaxy would make sense. Getting them to do these things so the tunarians could head right to Earth while their planet was being destroyed didn't. My Shep wasn't like that.
At the conclusion of the Mordin storyline, I cried because it was a poignant moment. That's emotion that the game evoked from an appreciable standpoint. I felt a connection to the character Mordin, and when the final moments played out, they felt true to both his character and mine.
Unfortunately, there were too many parts where the rest of the game tried to manipulate me into the same emotional reaction. Too many times where a character I thought for sure was dead would come bouncing back. Too many times where it seemed someone shouldn't have died, but did.
In particular, I rage-quit the evening I played through the asari temple. That was completely and utterly a stupid way to push the story along. I was winning the fight, and they threw in some random crap and made me lose. Excuse me? Really? Perhaps you should've taken into account the fact that sometimes Shepard wins, and then developed an alternative story from there.
I also nearly rage-quit when Thane's story seemed to resolve itself in cutscenes. Fortunately, that redeemed itself later with another, more honestly evocative moment. But still... manipulated to that end, I went dragging my heels into the ground, quoting my favorite internet cat, "No no no no no!"
But my most virulent dislike is the actual conclusion. You run a gauntlet of shooter missions and cannot save the game between the last handful of wave events, and so you're pushed along toward an inevitable conclusion that sells itself short by means of long exposition (how come I can't shank the Illusive Man?); confusing child character dropped in from pretty much nowhere (is this some sort of metaphor for something?); game mechanics no longer working as they had all along (why must I spend so much time hobbling along. Didn't I spend exhorbitant sums on the best armor which can heal me?); and meaningless choices at the end.
Oh, that's right. It's just a game. If I want something better, I can just wait for new DLC and pay for more. Which, by the way, is pretty much what happens! If you sit through the credits, you get a little WTF cutscene, and then a cheerful on-screen message inviting you to enjoy playing your Shepard again and buy some DLC.
On the bright side, I am now free to play my other imported Shepards to see how their romances and alignment affects things and won't have to play through that horrible ending ever again.
To that end, I imported my very first FemShep, created before I'd played ME1, and so it's interesting to observe the differences. This is Thane's girlfriend, so I visited him in hospital and was amused to note that my suggestion we take some alone time means we do the deed (or so it seems) in the hospital waiting room in front of a giant window. So much for privacy, Shep! :)