I've been watching Oobi with my daughter since before it was a full-length series -- it used to be just little filler bits between the shows on Noggin. It has been wonderful to see the program grow as they are able to longer and more involved stories.
The puppetry on this show is just wonderful. I'm constantly amazed at how they manage to get so much expression out of a puppet that is nothing more than a hand with a pair of eyes on top. In one episode, when Uma has a cold, you hear her sniffling, and there's a subtle movement of the puppet that lets you SEE her sniffling as well. There's a subtlety to these characters that just is not possible with regular puppets, Muppets, or marionettes.
My only problem with the show is the voices of Oobi and Kako. According to Noggin's website, Oobi is 4 years old, and Kako is his best friend, so presumably he is also about 4. But the voices don't sound like 4-year-olds, especially Kako's.
But that is a small issue compared to the wonderful interaction of the characters. When Oobi teaches Uma to say "neighborhood", or visits Kako's house and learns to eat okra, or goes fishing with Grampu, you see a sweet, intelligent child. No wise-cracks, no disrespect, just honest relationships in a loving family.