Doesn't Quite Take the Hat
In every set of Joker's Asylum, there are some good stories, and some mediocre ones. This happens to fall into the mediocre category. The main reason? Probably the art. Oh, and the fact that it follows the exact same storyline as half the other Joker's Asylums. Super-villain meets girl. Super-villain falls in love with girl. Super-villain wins girl's heart/captures girl. Something goes wrong. Super-villain goes back to being typically super-villain-y. Yep, that about sums it up.
The transition to picture book style was actually refreshing at times. And they did do a good job of keeping the Hatter in-character. Oh, and I actually liked the whole tea-obsession thing.
The Mad Hatter's mouth was just...not really drawn so well. It looked like his teeth had been replaced with a horse's hoof. And that distracted from the whole rest of the story.
Depends how much you like the Mad Hatter. If you're a fan, you should pick this up. If not, you might want to just leave it.