I'm 6'2" about 180 lbs., and I've been riding 159s my whole life. I hear you can go down a few centimeters with the BTX though, so would a 156 by right for me or should I stick with the 159? I've read all the reviews, but a 156 still sounds short to me. I'm looking for an all-mountain board, not strictly pow or park.
Since you're looking for an all mountain board 159 is a better size for you. also, you really only need a wide board if your boots are size 12 and up
The Lib Tech Travis Rice is a great all mountain board, and Lib Tech/GNU's Magnatraction is the real deal it cuts through snow and ice like butter
Go with the 159 but get the Carbon Credit!!!