I have been to the Monday/Friday night seafood buffet on multiple occasions & have enjoyed it each time.
Food: On the nights I've been, the buffet had (among other things) crab legs, peel & eat shrimp, and seafood risotto prepared to order. In addition, they had a kids section, a chicken dish, a steak dish, and desserts. Also, when you are seated, the waiter puts bread on your table and serves you a Caesar salad.
Characters: Garden Grove has characters nightly and on Saturday/Sunday mornings. On Monday & Friday nights, the characters are Timon

) my favorite

) and Rafiki; other nights, the characters are Goofy & Pluto (don't know who appears on Sat/Sun mornings).
Atmosphere: As compared to other WDW character meals, this one has a much more relaxed and upscale (but still casual) feel to it. They have a lot of different items that you won't find on most WDW buffets (probably since they don't participate in
DDP). Also, this character meal is quieter & less hectic; the characters aren't as rushed here as compared to other places, like CM or CP.