Update
The second pair of Summits arrived yesterday. I used both side-by-side for about an hour after work, viewing real-world subjects at varying distances (birds and planes) as well as more sedentary subjects (flowers, lettered signs, the mountains). The I took both pairs out again after dark to test them on lit signage targets. The replacement pair is a little better in a couple of ways: the sweet spot is larger and overall sharpness a bit better. The biggest difference is that with or without my glasses, the focus "snaps" better, and when it comes into clear focus I can actually feel my eyes relax to a degree not felt with the original pair. I went through the cycle of defocusing, refocusing with my left eye and then with the diopter a few times with and without my glasses (both pairs), and the new pair would settle into focus without the tiny back-and-forth adjusting that the first pair seemed to want. It could be, as Charles (from Zen-Ray) suggested, that the first pair got some rough handling, or it could be that they simply fall at the the bottom end of the "acceptable" range and the new pair was assembled a bit closer to the ideal specs. Either way, I'm closer to experiencing what SteveC wrote about in his original review. At about $175 these are quite a bargain. In the past few weeks I've tried out several pairs of 10x binoculars from $100 Bushnells to near $2K German and Austrian models, and the ZRS seem closer to the top group than the mid-bottom group. The biggest difference between it and the alphas (for me) was the crispness out close to the edge (I especially liked this in the Swaro EL line), but using these handheld I'm not sure that's much of a functional issue, since I'm scanning through the center. The color cast, while warm as others have noted, doesn't bother me. In fact on a morning like this one, with rain clouds in the sky and an overall bluish cast to everything, they're actually kind of pleasant. They have a decent "3D" feel around the focus area but there isn't a whole lot of DOF when you're not viewing near the infinity point.