Sorry - I'm not a guy but want to weigh in...I HATE them. And I used to sit by this lady at work and all I could hear was her fake nails hitting the keyboard all day. It was driving me insane! Plus aren't there some sexual things you just can't do with these things. (Sorry if that's TMI)
OK, to everyone who has commented, french tips are NOT necissarily fake nails. I paint on my own french tips to my natural nails all the time and I have pretty short nails. I think the natural ones look classy and some of the short fake ones that still look natural are still pretty nice. It sometimes depends on the girl and her personality (girly-girl etc.) but mostly it depends on how long they wear them.
I don't like the round kind only the square kind. I used to have them..well really it was a coat over my natural nail. I don't think guys really like them, it is one of those girl trends that girls like but guys tend to find unattractive.
They get annoying and in the way of things. Also expensive. And they damage the nail underneath it until your new nail grows in, which takes a few months.
The biggest pro is that your nails always look polished, and the polish doesn't chip, and if you keep them short they won't look all fake and talon-like.