I gleaned a lot from these boards here and tried a few things and am here to report. [Though I didn't eat there (based on poor Hound reviews), Fat Mama's Tamales is open (there had been a question about that)].
Cock of the Walk: Quite good; catfish was fresh, moist; hushpuppies were moist with just enough frying grease to make them tasty; fried oysters, plump, fresh, with light breading. Pot o' greens were passable. I have been suprized to not find greens on many of the menus in MS.
The Sandbar in Vidalia: Disaster. Catfish, dry & tasted like the bottom feeder it is; oysters dried up and over cooked. The Vidalia onion blossom was wild surprise. I was expecting something on the order of fried squash blossoms but instead got the largest onion I've seen, splayed open (i.e., the blossom) and deep fried. Though it was tasty, it was easily enough for 4 or more.
Pig Out Inn BBQ: Fairly good, no sauce, smokey, with tender pieces. Not the best I've had but satisfying.
Didn't eat at the high end places (The Castle, Carriage, Monmouth, etc.) as I was in the mood for local food and am on my ways to NO. However, all the reports were that they are quite good, esp. for MS.
As an aside, the Under The Hill bar was great place for beers while looking at the Mississippi and looking at beautiful/ghastly decrepitude (both of the bar and the habitues (i.e., drunks, including the tipsy owner). Nice to see a funky joint in the midst of this historic (& quite nice) city.