Marc/Michael,
I have looked through both of these, outside, in various conditions, but not side by side.
The 6x specimen of Yosemite I tried was not a good one, at least in comparison to the 8x version which I tried alongside. It seemed like a collimation issue; all I know for sure is that it really strained the eyes trying to get a good image. However, the 8x specimen was quite impressive, especially for the money. Image wise, I did note that they exhibited some undesirable effects in challenging lighting situations; it was not an extreme negative, just some noticeable glare/ghosting from streetlights for instance.
The 6x Katmais were very nice binoculars to my eyes. The only real issue was that I just couldn't seem to see enough detail. It could've simply been the 6x power. It could've been the BAK7 glass. Either way, I was still impressed enough to strongly consider the 8x version. The only problem was the narrow FOV. Stray light, back-lighting, etc was NO problem with the Katmais. The size is very handy and (for me) still very easy to focus, etc.
In comparison, given choice between the two, I would go with the Katmais in either power version, as long as price was not a consideration. The quality/price of either model seems reasonable. If the Katmais had a wider FOV in 8x, I would probably own a pair.
FWIW: It seems like most here have preferred the 6x EO Ranger Platinums. I've not looked through those to compare.
Hope this helps, APS