Snap Sanp
I have a Sigma EF 500 Super (GN=50) which is mint, used less than 5 times since I bought it in 2002. This flash can do 3D TTL flash, have a bounce and swivel head, can do manual with variable power ratio, slave flash etc. Only thing it cannot do is wireless TTL and non-TTL Auto flash compared to the SB 80DX. But the Sigma is of course much cheaper, a new one now (new model) would cost about $350. I would be willing to let go mine for about $200. Let me know if you are interested. Can PM me.
regards
NICK