Which brings us, as they say, to the best of the bunch! I don't like 10X binoculars. I find them too difficult, too uncomfortable to use for extended periods in the field. I am convinced that you see more, over time, through excellent 8X glasses than you ever will through 10X glasses. I say all that so that you will appreciate the impact of this next: I like the Swarovski 10X42s, and, what is more, I would certainly use them for my primary, day in and day out, birding binoculars.
Part of it is, of course, the excellent optics. On the bench they measure right up there with the best optics I have yet tested, coming within a tenth of an arc second of the Swift Audubon 8.5X44s. Image quality is excellent. Contrast, as you might expect from the comments under the 7X42s, is exceptional. On the Color Extinction test they do as well as the 7X42s, and on Twilight Resolution they score higher by a factor of two than any other binoculars I had available for testing! These are exceptional optics.
It has more to do, however, with their handling features. They are exceptionally well balancedÐit is easier to hold them steady than most high power binoculars, but the real source of their ease of use is the combination of wide field and exceptional depth of field. They simply do not have the finicky, restricted, focus I associate with high power binoculars. They are easy and natural to look through. (For some unknown reason they lack the locking diopter ring of the 8X30 and 7X42, though it appears to be the same concentric ring. It does seem to stay put well even without the lock.)
The real kicker though is the addictive nature of the large image. Admittedly the 10X image does not deliver significantly more detail to the eye in most situations, but it is certainly attractive. The bird is big! Without the handling drawbacks of most high power binoculars, that big bird effect makes it very hard to go back to 8X or 7X binoculars. Yes, I do experience somewhat more fatigue using the 10X42s than I do with 8.5X or 7X glasses, but, with these glasses, it is worth it! I would still love to see what an 8X42 Swarovski would be like, but for now the 10X glasses are fine indeed. Given their waterproofness, their exceptional resolution, and their twilight performance, I have to give them the Reference Standard for high power binoculars. The Celestron 9.5X44s are still slightly better at extracting color detail, appear just a shade brighter in the field (though with lower contrast), and have a very good feel in the hands, but, overall, the Swarovskis edge them out. I would not carry the Celestrons as my day to day birding binocularsÐI would carry the Swarovskis, and that, to me, says a whole lot about their general quality and field worthiness!