What is interesting now, starting this past year, is that the Grammy not only goes to the producers and writers but also to the primary vocalists. Here are the nominees and (of course) my opinions!
FOLLIES (Jan Maxwell, Danny Burnstein, Bernadette Peters, Ron Raines, & Elaine Paige) - I think this one has a good chance of winning. In my opinion, leaving out opinions on the performers themselves, this is probably the best cast recording I have ever heard in terms of preserving a show and mirroring the true theatrical experience.
THE GERSHWIN'S PORGY AND BESS (Audra McDonald, Norm Lewis, & David Alan Grier) - I really like this recording and it has some great performances. That said, I think it deserved a nomination, but won't win the award.
NEWSIES (Jeremy Jordan & Kara Lindsay) - Similar to P&B, it is a great recording that deserved to be nominated, but doesn't stand up to some of the other nominated recordings.
NICE WORK IF YOU CAN GET IT (Matthew Broderick & Kelli O'Hara) - I thought this recording was pretty boring with so-so vocals. This is like LEAP OF FAITH getting nominated for the Best Score Tony Award.
ONCE (Steve Kazee & Cristin Milioti) - "Falling Slowly" has already won awards, and even though it lost the Grammy, it has a good chance this time. This is a gorgeous recording of gorgeous music. I also think it has broad enough appeal to be noticed by Grammy voters who won't appreciate some of the other recordings due to their very musical theatre feel.
Also, "Let Me Be Your Star" from SMASH was nominated for Best Song for Visual Media. Do I think it will win? Probably not. Should it? Probably.