Great if you enjoy ripping your own heart into pieces.
I finally finished the single-player campaign on ME3 last week, which in itself was the perfect balance of challenging combat and interesting plot (I chose the Role-Playing option, obviously). It took forever but I never felt like it was just dragging on- there was always something to do, someone to talk to, somewhere new to explore. I also felt like the combat itself was a great step up from ME2, and the controls seemed a lot slicker. Overall, aside from a couple of glitches and the occasional character not popping up in a cutscene (way to ruin the final romance scene, BioWare), it felt to me like this game was really well done.
But finishing it? Watching how my own actions/apparent stupidity affected the characters I'd grown to love? It broke me. I don't particularly care what the rest of the world thinks of the (admittedly controversial) ending; personally, I was a complete emotional wreck.
Which, in my books, makes Mass Effect 3 a winner. Hurrah.