Binoviewer Performance Questions

Hi All,
My questions are probably too boring to many but I'm trying to understand many of the issues in the binoviewing arena.
Is performance a major issue?
What is it that determines the performance of a BV the most? Aperture, coatings...?
What is it that most determines which BV to buy? Optics performance, other features, manufacturer, warranty, cost...?
If we hope to attract others to binoviewing, offering them information that answers many of their questions seems a logical way to help. The reasons for my personal purchases are probably not the same as many others. Any help and opinions would be appreciated.
Thanks,
TomM

In a SCT,clear aperture and AR coatings.These two criteria will yield the best DSO performance.
Satisfying performance can be had with smaller clear apertures and less than state of the art AR coatings but DSOs take a minor hit when compared to the performance of the biggest clear aperture units.For refractors and newtonians some sort of OCA is generally required to reach focus.
The light transmission effectiveness of the OCA and the ability to reach focus in your scope with the bino-OCA combination is critical. It is here that smaller apertures don't pay as big a penalty on DSOs as the OCA can off-set to a degree the vignetting that takes place.The only obvious down side to a smaller clear aperture is vignetting on longer FL eps. I am limited to a 26mm FL ep with BW-Optics binos before the edge
of the field ceases to be fully illuminated. My TV binos will work
with much longer FL eps before the edge is under-illuminated. Practically the performance differences between the two binos are not large when the equalizing effect of the OCA used with them to reach focus is factored into the equation. The above comments only apply to properly constructed and internally baffled binos. The quality
of construction must be present first.