I have owned and used Swarovki, Leica, and Minox. Currently my roomate has a pair of Swarovski 10x50 SLC and I have used them on many hunts. I currently own a pair of Leica 10x42 BN and a pair of Leica 8x 32 BA. I used to have a pair of Minox 8x32. I have compared them all side by side many times and will try to give my opinion.
To my eyes and my roomates the Leica's are the best. The Swarovski are a top of the line bino and the low light performance is neck and neck between the two. But the Leicas seem to produce a slightly sharper, clearer, and cleaner image than the Swarovski. I agree with Chris that the Leica have the best construction, they are simple awesome. On the Swarovski 10x50 the focus wheel is too rough in spots and too smooth in spots. The Leica focus wheel is perfectly smooth and consistent throughout the entire range. My roomate and I both prefer the Leica although they are both top of the line.
I bought a pair of Minox 8x32 after my first pair of Leica 10x42 because I wanted a smaller bino for football games, turkey hunting, ect. I liked the construction but never really was happy with the optics. Don't get me wrong the optics were good, maybe even great, for the money. They just weren't nearly as good as the Leica and once you get used to looking through top of the line binos it is hard to be satisfied with anything else. I ended up buying a pair of 8x32 Leica and before I sold the Minox I compared them side by side. The one thing that stood out right away was that the Leica were razor sharp from edge to edge where as the Minox were only clear in the center. Keep in mind the Minox I had didn't have the ALT glass that they use now. I also disliked the Minox focus wheel, it was way too smooth and sensitive, which made it hard to keep focused.
The only difference between the Leica BA and the new Leica BN is that the BN will focus closer. They improved this for birdwatchers so they could view birds 10ft away, but it doesn't make any difference to a hunter. When they launched the BN line a few years ago they also claimed that they created a new HDC lens coating to make the BN more scratch resistent. I think that this was more marketing fluff than anything else. Whether you buy the BN or BA, you will not notice any difference optically or mechanically between the two. The Ultravids came out this year and are designed to be lighter than the Trinovids. They also claim to have developed a new prism coating. I couldn't tell any difference optically between the Ultravids, Duovids, or Trinovids. To me, they are all razor sharp optically, but the Ultravids are a fair amount lighter than the Trinovids and alot lighter than the Duovids. You also will pay a good bit more for the Ultravids because they are lighter.
To me Steiners are not in the same league as Leica, Swarovski, or Zeiss at least not any that I have used. I would recommend to go with the Leica and you won't regret it. One more point, to me the 10x50 are twice the size and a good bit heavier than the 10x42 and very little if any improved performance. I am not trying to talk you out of a 10x50 but for hunting you may want to take a look at a 10x42. I have used them both and think the 10x50 are just too big and are not noticably brighter than the 10x42. They are very close. Just my opinion though. I hope I have been a help. Feel free to post any more questions and good luck.