OK... back to the orignial question.
I've got a couple of Leica binoculars and I've played with the Leupold Gold rings in general and those 10/17X42's at least casually once. I've also owned or tested lots of other binoculars.
First of all, any Leupold Gold Ring binocular is an excellent life time warrantty binocular not limited to the original buyer. No, they aren't as good as the latest Leicas, but they aren't much less in optical performance. They and the other $1000 class stuff like the Pentax ED's and the Meopta/Cabela's Euros are really so close to the Big Three that many us question the need to spend the extra money.
However, at 17X you'll run into a problem. As the magnification increases, especially if it is done with a smaller objective binocular, the net effect is the more rapid decrease in image quality. A quick comparison between a quality 15X56 and the above Leupold will quickly show you what this is about.
That's not to say they aren't useful. But, they would, in no way, compare to something like the Leica Duovids at 15X or a Swaro 15X56.
In the end, you are the best judge of this. My advice is test them at extended distance yourself and see what you think. Compared to the cheaper Nikon zoom or their cheap 12X50's, I think you'll find they are better. But then try stacking them up against a good Pentax SP or a Pentax ED in the 12X50 size.
BTW, I've done what you are trying to do, but in a different way. I usually pack a light 6X or 8X binocular around my neck and carry a larger, more powerful binocular or spoting scope in my pack. If I'm glassing, trying to find game, a big binoicular works best. But if I'm judging heads, a spotter works better as a rule. E
