I used to be completely head-over-heels in love with Hannah, but Miley Cyrus killed it. Without that association, I'd say it's lovely and definitely classic and timeless, but definitely being overused at the moment. I think as a middle name, it's neglected and would make a nice "fallback name" for a more exotic first name.
As Circus Lullaby said, the original Channah is lovely. I'd probably go for that over Hannah.