I have a pair of WO binoviewers, and I'm very happy with them. If I won tatts I'd spring for a pair of Denkmeier's with their bigger mirrors, but until then I'll stick with the cheaper two eyed view. I don't notice any vignetting most of the time. Much more relaxing for prolonged viewing (& sketching).
I thought that the SV, WO, Seiberts and Burgess Optical versions were all basically rebadged versions of the same thing, with perhaps some QC differences in the selection process after manufacture.
