The main thing I like about the Cave shooters are the options. There's a control scheme, difficulty setting for just about any type of player.
I love them. For some reason, I find them extremely relaxing, perhaps because they demand so much focus. Games like Noiz2sa and rRootage are fantastic. I love all the action on the screen, and love the crazy stuff the Japanese think up. Bullet Hell is my favorite genre. I'd like to see iPad or Universal versions of the Cave shooters.
Bullet hell/curtainfire shmups are actually my favorite genre of games. So, no, they do not give me a headache. In fact, I might go so far as to say they heal any headaches I have
Yuceick! Bayonetta is the one of the worst. I love Asian countries for their food, their motorbikes, their tradition and their technology. But not for their messed up anime/gothic games with stupid guys with white spikey hair carrying swords like twice the size of themselves and the chicks in catsuits with weapons that so many people are sexually aroused by. I just find them creepy.