Adorable, fast-paced, funny, and perfectly clean. We're two mid-twenties adults and are enjoying this show far too much. ;)
Sure, it's repetitive. Every episode basically has the same plot structure and several other repeated elements. But within that framework, it's super creative - similar to the random stories my sister and I used to make up when we were little. Throw in some clever pop-culture references and lots of original songs (usually one per episode), and you've got a show that's fun for adults, too.