Les Miserables has too much controversy surrounding the direction, too many nay-sayers about the performances of a few of the actors etc, and too many mixed reviews (currently 70% on RottenTomatoes). It's only being driven by the hype of finally seeing the musical on the screen, and that's not enough to garner a Best Picture win.
Even though Lincoln has consistently high reviews (91% on RottenTomatoes), I'm not sure that's going to translate come Oscar time because as you said, a lot of people from what I've heard, in spite of them thinking it was a good movie, have left the theatre feeling underwhelmed. Add in the fact that Spielberg has had a few other Best Picture winners before, and they might pass him over for someone else. I think it has a better chance in the acting categories.
Django Unchained has fairly high reviews (89% on RottenTomatoes), but considering the current political move to crack down on gun violence in general, but also in movies, I think the Academy is going to play it safe and not vote that one as Best Picture. It does have a good deal of support, but most of its nominations in other ceremonies have been for either the screenplay or the supporting actors, so obviously the thought is that it doesn't have a chance at Best Picture.
Amour has the potential to be 2013's Life is Beautiful, and I wouldn't count it out for an upset win for Best Picture, but I'm not sure there'd be enough votes for it. I think if that movie has any chance of Oscars it'd be more in the acting category or Original Screenplay.
Zero Dark Thirty, in spite of its critical acclaim, is viewed as being too "dangerous" and too "political" at the moment, in a manner of speaking, hence Bigelow's snub. Add in the fact that Sony has never once won Best Picture in just over 20 years in the business, and that also speaks volumes about their ability to campaign come Oscar time as well. It has, to put it bluntly, absolutely no chance of Best Picture at all. Its best chance is with Jessica Chastain for Best Actress.
Life of Pi is a great cinematic achievement, but it's just not as high-up on people's list of "Best Movies of 2012" to get enough #1 votes.
Argo, as you could already see by Ben Affleck's snub, isn't held in too high regard by the Oscars. Yes, they view it as a fine achievement of cinema, but not the best for 2012 (in spite of having the best RottenTomatoes score of all of the Best Picture nominees), and its best chance would be in the screenplay and acting category for Alan Arkin.
So that leaves Silver Linings Playbook, which is probably right now viewed as the "safe" option in the eyes of the Academy. It deals with a worthy subject (mental disorders), the thin tightrope between drama and comedy is done very well and to great effect from what I've read from some of its glowing reviews, it's not too "in your face", and it's gotten many Best Picture nominations from other awards ceremonies, so a lot of people see that it's a worthy contender. Add in the fact that it's currently sitting at 91% on RottenTomatoes, and its expansion next weekend which allows more Academy members to see the film (or see it again), and I think it has a good chance.
(This is just my personal analysis, so take it with a grain of salt.)