I'm keen to know too Matt.
There is a very good review about the 13mm Nagler on this site which is well worth reading. See
http://www.iceinspace.com.au/index.p...42,245,0,0,1,0
Bintel have them going relatively cheap at the moment so the Ethos would need to be mind blowing given you could get a couple of Naglers or a Pentax or two for the price.
Cheers