I think Casey is a great name for a boy! It's slightly more common for boys (when you add up the various spellings common on girls it's pretty close). As for gender confusion, I think with the near-even gender ratio people may sometimes question but chances are completely wrong assumptions won't be as common as if you went with something like Ashley.
Dislike. It is too feminine for me.
I went to school with a boy whose surname was Casey and the cousins of the family across the street had Casey as their surname too. Therefore, I see it as a surname.
I do however, know a boy called Casey, who is the brother of one of my best friends. He's in his twenties and named his baby son after himself a few years ago.
I know a handful of male Caseys of different ages, and they all wear it well. Casey is definitely still viable for a boy. I like it.
Casey is one of those unisex names where I don't really have a preference about which gender I like it better for.
The only Caseys I know in real life are boys (including the son of my mom's best friend, who's 17), but I've seen Casey used for girls on tv shows and movies.
I think it's a great name. :)