I had Leica geovid 8x56 HDs and they were nice.. Optically great, electronics a bit 70s and design wise very dated... After trying a pair of Zeiss I sold the Leicas and replaced them with Zeiss 8x45 rfs.. My eyes certainly can't see any difference but one thingthatbis different is the way Zeiss shape the lens.. This actually bends the image at the periphery which stops the sea sick feeling one sometimes gets when panning for long periods.
light gathering of the Zeiss x45 is as good if not a bit better to my eyes than the Leica x56 but that is subjective.
the electronics of the Zeiss is much more up to date offering m or yds.. None of this choosing at the outset! I also prefer the button location under the right index finger rather than the left of the Leicas.
Target acquisition is much more straightforward with the Zeiss. With the Leicas you have to press the button to turn the system on and then centre your target and press again together the range... With the Zeiss as you press the button the system comes on and the targeting reticule appears, releasing the button gives the range so far more intuitive, faster and less prone to error... Also whilst it is not going to matter in the field, (I noticed this target shooting) the Leicas would return no reading quite often beyond 5 or 600 yds, the Zeiss never fal to read up to 1k and beyond. Also, ranging is faster on the Zeiss but I think that comes down to better & more up to date electronics.
ergonomically I much prefer the Zeiss (which was what made me think about switching in the first place) even though they are MARGINALLY heavier than the Leicas BUT i believe Leica are bringing out a new version which looks very similar to the swaros, in which case the ergonomics will be brought bang up to date.
so... There you have my opinion of the 2 I have owned... I would not go back to Leica in their present guise but optically they are great although as I found the Zeiss x45 as bright as the Leica x56 I would assume that transmission is better with the Zeiss.. I also like the spherical lenses, they do make long periods of glassing more comfortable.
as for the swaros, I spent a good half hour playing with them at bisley live and then again at the shooting show and whilst optically they were as good as the leica or Zeiss they were certainly no better and didn't feel as robust as the Zeiss.. Electronics were no better than the Zeiss and they have big lumps coming out of the bottom of each barrel, presumably to accomodate electronics or prisms.. I found that very uncomfortable in the hand. So whilst they are undoubtedly capable bins I couldn't see me holding them for hours on end plus they are much more expensive. Even if they were comfy to hold they certainly weren't (imho) worth any more then the Zeiss or the Leicas... Just bling!
hope that helps
Paul