I made an forum post about AC3 (here*) that ended up turning into a one-sided rant.
Generally I went in biased. Brotherhood to this day is the one that I have the most fond memories of (I'm playing it right now after AC3 and am loving it once again). I didn't know what to expect with AC3. I expected to love it but I was mostly confused by it. Design choices I mean. It has some wonderful moments that are marred by a multitude of nipping issues that really detract from the experience. The story is fantastic, the characters are wonderful (Connor is a more believeable and grounded protagonist than Ezio was and I was totally behind him all the way) and the animation/graphics are beautiful. But the gameplay just doesn't sit right with me enough to completely enjoy it. The freerunning is arguably the best it has ever been but that's about it. I can fight and fight well but it feels more clunky than before and enemies are more annoying than is necessary because of it. I spent the game avoiding fights compared to picking them in the past games.
And all that's without mentioning the glitches. It's just jarring. There was absolutely no glitches I encountered in the past games so it's definitely going to stand out this time. I read something on TV Tropes that seems to help explain it. The 21 December deadline Ubisoft set themselves, in a rush to get it out they missed some things. (Don't get me wrong it's no Sonic 06, this one is playable but nevertheless it makes sense. Not excusable but makes sense.)
Overall, a pretty flawed but still worthy game if for the experience. (The music's gorgeous...)
*Not one to self-promote but here, if you're interested at all. You can debunk, refute or agree with me if you like: http://www.gonintendo.com/boards/viewtopic.php?f=4&t=102117