I selected the 711....but you can't go wrong with any of these blades.
I think it really comes down to overall length and weight.
If trying to stay light the 511 is a no brainer..... <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" />
If you can deal with the extra weight, the 711 is more versatile..... <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" /> <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />