Both are good harems that don't spare on the comedy. Ai Yori Aoshi is more of a love story than a harem, and Ai Kora is more of a harem than a love story. Regardless, if you like the essence of harems and lots of comedy you will like either one.
Both stories are harems, of sorts, where the primary love relationship is more or less evident from the start. The rest of the girls mostly provide comic relief. Ai Kora is much more absurd in its humor and much less poingant in its moments of truth, but both have the potential to make you laugh and to tug at your heart strings. If you liked one, the other is at least worth a perusal.
Urashima Keitarou is a loser. He's failed the Tokyo University entrance exams two years in a row, and his parents have finally kicked him out of the house. Penniless and destitute, he travels to his grandmother Hinata's inn, hoping she'll put him up until he can get into Tokyo U and fulfill his promise with his childhood sweetheart (whose face he can't even remember). Unfortunately - or perhaps fortunately - it turns out that the inn is no longer an inn... it's an all-girls dormitory, as he discovers in his typical blundering fashion by grabbing an eyeful and more of every girl in the place! Narusegawa Naru, a fiery-tempered high school student and the first victim of Keitarou's lewd bungling, wastes no time doling out brutal punishment and preparing to kick him back out to the street. But wait! A letter has come from grandma Hinata, and Keitarou is to be the dorm's new live-in manager! Is this a blessing from heaven, or has he been cursed to a living hell?
These harem manga are two of the few harem style manga not about high schoolers. The style and focus are also very similar being more romance than comedy but not skimping on the comedy.
Both Love Hina and Ai Kora are very similar. Both feature a "destiny" plot in which the main guy and the main girl are supposed to be together. The only difference between the two is that in Ai Yori Aoshi, the girl actually wants to be with the guy. Both are sweet, comedic, and all around good romance stories.