Originally Posted by anap
It is a specialized frame....
I still say you need to ride it to be sure.
There are many different 6' body types out there - leg length, arm length, torso length will all have an impact. It also depends on what the intended use of the bike is. Are you buying an XC bike? Downhill bike? Freeride bike?
FWIW, I prefer a 19" in a Specialized for XC use. The 17" feels a bit cramped for me.