I'll be turning 40 later this coming summer. Except for the fact that I was out with a busted up knee from a mtb crash, I have to say I was in better shape at 30 than at 40 - physically, at least. Emotionally, financially.... 40 is looking better.
I can't really say that I'm looking forward to, or dreading, 40. It just is. Not much I can do about it, and as someone said....it's better than the alternative!