I built myself a mirror mount using an FS mirror from
http://www.fsmirrors.com/
I found it great for smaller binos-upto my 11 x 60s -but not so great for my 20 x 80s
dewing is an issue, as is the issue of it being harder to find stuff because of the image reversal issue
personally I find it very pleasant to sit and observe with a mirror mount -but in the end it comes down to personal preference-its a holden vs ford comparison-when you compare to a parrallelogram mount