No Country For Old Men (+3)
Strengths:
1. It has won every precursor under the sun
2. It has a passionate fanbase
3. Though not enormous, it has been running a good box office performance for almost three months straight
4. It has the most critical acclaim of just about any nominee, along with There Will Be Blood
5. Due pedigree and strong in the technicals
Weaknesses:
1. It's dark, really dark
2. It may just be too niche

There Will Be Blood (+1)
Strengths:
1. Huge critical acclaim
2. Passionate fanbase
3. Pedigree and again, a strong technical showing
4. Has a mad-classic feel
Weaknesses:
1. Box office is not that strong, though it'll certainly be profitable
2. It's possibly more nihilistic than No Country
3. Hasn't really won much, though it has certainly had tons of nominations

Juno (+1)
Strengths:
1. Fanbase
2. Largest box office take
3. It's the lightest film of the bunch and the most mainstream-friendly
4. The director's nom
5. Has solid support from most of the right people
Weaknesses:
1. Has had a bit of a backlash
2. No editing nomination
3. Would require a stretch to win 3 Oscars, the smallest take of any BP winner in years. And it ain't winning Director.
4. Has won no precursor for Picture.

Atonement (0)
Strengths:
1. It's a very classical film
2. Uh...the Globe?
3. Good enough box office take
Weaknesses:
1. No Director nom
2. Only mildly passionate support
3. Won nothing other than the Globe

Michael Clayton (-1)
Strengths:
1. Um...it's plenty straightforward?
2. Longevity
Weaknesses:
1. No wins for Picture
2. No passionate support
3. Fairly middling box office take

No Country For Old Men additional pluses:
1. The directors are the front runners for the win (BP and BD wins often go hand in hand)
2. Has an actor who's favored to win in acting categories (Bardem)
3. Favored to win in Screenplay category
4. Tied with TWWB for most amount of nominations

There Will Be Blood pluses:
1. Actor favored to win
2. tied with NCFOM for most amount of nominations

Juno:
1. Favored to win O. Screenplay