It's very fun and very good !
There's a lot of humor, but there's still some drama and the animation is good.
The plot isn't as intricate as, let's say, Avatar : the Last Airbender, but it's stay interesting. The show seems childish, at first, but some of the lines are really "adult oriented" and there's a lot of shout-out and references. (D&D, blood bowl.)
The actions is going crescendo on the first season, the drama follow accordingly.
I used to see it with my 3 years Daughter, she liked it, and so did I.
I do not know Oban Star Racer, but It seems cool, I will check it.
Here's the opening (In french).