Treme is watchable if :
- you have extensive knowledge of New Orleans culture (music, social, hurricane, customs, people, institutions, etc).
- you don't mind a tv show spaghetting its stories without any point or direction.
- have manual selective memory, where you can erase stuff from your mind once you've watched it.
Otherwise, and especially if you're a David Simon hardcore fan, stay away from Treme, it will just make you sad about how an ambitious tv show with great actors and awesome showrunners can be ruined bigtime with bad decisions (or no decisions, for that matter). The main problem of Treme (on which it also succeed at accurately depicting the general feel of New Orleans people post-Katrina) is boredom. Absolute, alienating boredom. Every character is bored. Bored because they have shitty lives, bored because they're struggling, bored because they're bored. Every story is boring. Whiteknight cop fighting against the tide, musicians living the boheme life, families struggling in FEMA trailers, it's so boring it's depressing.
I'm a huge fan of David Simon and I love Homicide, Generation Kill and of course The Wire. I still don't understand why he did Treme, but to me it feels like the guy got money and went like "hey I like New Orleans, let's go film some shit right there, oh and I also love dem musicians, I'm gonna put them in my show, fuck acting and we'll write the story as it goes". I hope he'll come again with some good material, but Treme is for me a no-go.