Onipan! is a show about 3 oni girls joining the human world to improve the general opinion of how onis are viewed. The main gimmick of the show is that when they need help, their sidekick, Kuma, will give them the Oni tiger-striped pantsu (hence the name OniPan!) and they will transform magical girl style into the outfit needed.
If 60 episodes seems too daunting to pick up, allow me to explain that each "episode" is very short. Each episode aired at different time over a week and were compiled into a full 12-13 minute episode later. With 5 mini-episode in each full episode, that makes the show clock in at only a little over 2 hours.
Another thing to make mention of, this show is a very Japan-styled comedic show. You need to understand the basics of what oni are in Japanese folklore, like the story of Momotaro. This show also does a lot of references to other media which include: Dragon Quest, Yu-Gi-Oh!, Food Wars, The Phantom Menace(?), Sailor Moon, and other things I may have missed. The comedy will be a hit or miss depending on whether you can enjoy the subtlety of the humor and the fact that the show doesn't take itself seriously.
My honest opinion is just let your brain relax and enjoy the goofy antics and 4th wall breaks. This show does a really good job of what it set out to do and the shorter episodes help keep the simple plots from going on too long.
All in all, it gets an 8. It's not a masterpiece, but it's good enough to binge in an afternoon and relax on the couch watching.