I think is a bit small for you or you use a big road bike. I'm 5'8" and have a 16.5" Giant VT2, 18" Kona Unit and a 54cm Orbea Volata.
I also agree that the proper sizing is more important on the roadie but a bike too small isn't ideal, too small and you'll be cramped. On the other side the VT runs a bit on the bigger side of sizing and it has a higher stand over clearance than most bikes around and that why I went with the small.
Play with several stem, handlebar and seat post combinations until you get it right. In my case I'm using a 90mm stem, 1.5" riser bar and a setback post.
The VT is a sofa, there are not many bikes around with that much travel that can climb as well and are as comfortable as the VT; it's a shame that Giant took such a nice bike out.
