I've given this a try, mainly because it's created by David Simon, who did The Wire, and Generation Kill. The former is the best thing I've seen as far as T.V. goes and the latter I never finished but enjoyed to an extent.
Treme is about the lives of people post-Katrina in New Orleans. There are a few of the actors from The Wire in it. I watched the pilot and can probably see why people may enjoy it, and why it may (or is) doing fairly well. Sure, it's got everything you'd probably look for in a good T.V. show (think HBO) -- but I guess it's because I'm seeing the guys from The Wire not be the guys I'm used to them being.
It just doesn't interest me. There's no equivalent to Jimmy McNulty, Stringer, or any other of the characters that Simon created In The Wire. Perhaps I'll try track down Homicide: Life On The Streets.