Kappa Mikey didn't seem like the show I would like, especially since the commercials used to advertise it usually showed Gonard doing something disgusting. But one day, I finally decided to give it a chance, and before I knew it I was recording episodes and laughing all the way through them.
Mikey stands out among the cast as being the only main character drawn like an American cartoon, and honestly, I liked that. It's just one way of showing how different American and Japanese cartoons are in terms of style and expressions (e.g. How Mikey's expressions aren't as exaggerated as his friends.) But the designs of the characters are simple at best, nothing groundbreaking or exceptional. The Flash Animation is rather average, but the characters admittedly look strange, and even wooden, especially against the backgrounds and a few CG objects. Overall, the animation is not great, but it's something that you can look past.
There's no real plot to the story as well, and many episodes tend to simply screw any continuity or pretty much lead to gross out. Not everyone is going to like the humor, and there are definitely moments where you can't help but feel a tad disgusted or annoyed. Even so, there are a handful of gems that do indeed shine: Battle of the Bands, Mitsuki Butterfly, The Karaoke Episode, A Christmas Mikey, and Splashomon are this troper's top picks, in terms of animation and/or humor. The songs on this show are also incredibly catchy. Guaranteed, at least one song from The Karaoke Episode will be stuck in your head, whether you liked it or not.
The characters are also a big case of either you like them or are annoyed by them. Personally, I like them all, but even I know they will not appeal to everyone. They're not perfect, and at times characters will stray into Gross Out humor, but there are plenty of moments where they prove to be just a fun bunch of characters. It helps that the voice actors, particularly Sean Schemmel and Michael Sinterniklaas, clearly have fun with what they're doing.
In conclusion, it is definitely not a great show and they could have done so much better, but it is not a bad show either and it does have its genuinely funny moments. So really, if you haven't seen it, give it a chance and find the episodes I listed above. Would you regret it? Maybe, but at least you gave it a chance.