Having both, I offer the following observations. Personally I would take the 7x36 over the 8x43. Why? The 7x36 has a nearly porro like depth of field and resultant 3-D effect. Couple that with the very wide field of the 7x36 and that gives a combination found in no other roof that I know of. Also the very deep depth of focus makes the 7x36 as focus free as any binocular I have used. Additionally the 7x36 is enough smaller than the 8x43 to be much easier to pack around all day. The main drawback to the 7x36 is that there is some edge distortion. That bothers a lot of folks, but frankly it is to be expected with a fov as wide as the ZEN. Truly flat field seems to be the attraction (well one of them) with the $2,400 Swarovision.
The 8x43 seems to have a bit less edge distortion (frankly neither one has enough distortion to bother me). The magnification difference between 7x and 8x is pretty indistinguishable in the field to my eyes. But magnification preferences among various users are hard to predict.
I pretty much use the 7x36 as my first choice out the door binocular, and frankly I have never noticed any handicap having "only" 7x.
Edited by Klamath - June/12/2010 at 18:22