Avery Brooks as Sisko is on the fine line between serenity and complete insanity. Avery Brooks himself is kind of a weird zen grandpa. Dude's my favorite Trek captain. Yeah, his acting is extremely theatrical.
As a whole I actually think it stands up massively better than TNG. Both shows have a weak first season and both start to hit their stride in their fourth. DS9's final season is extremely good serialized TV, especially for the 90's, while TNG's final season ranges from spectacular to miserably bad with little in between. The worst episodes of DS9 (Melora, Meridian, Let He Who is Without Sin) are atrocious but the worst episodes of TNG are somehow even worse (Code of Honor, Subrosa.)
I actually think Kate Mulgrew's pretty good as Janeway too! Her first officer's the one sleepwalking through the whole thing. Voyager's overall mostly bad but it's still like 25-30% decent. I know that's not saying much.
Super Walrus Land: Mouth Words Edition