I pronounce it DAY-na and that's the only pronunciation I've ever heard. In the US that's the one that's most commonly used. I don't like DAH-na because it sounds the same as
Donna, and I don't like DAN-na because it sounds like someone saying
Dani funny.
I think it feels a little dated, but not terribly so. I've known a few female Danas and all pronounced it the way I do. They were all about my age. I like it pretty equally on boys or girls.