I too own a pair of the 15x56mm Swaro. Of all the Swaro options I bought these first. I live in Idaho and I have a 13 year old son who keeps drawing amazing tags. Being new to western big game hunting, but now seeing how big and wide open this country is I am learning how imp it is to find game up to 3 miles away. Well, if you live in country like me, no other glass will do it for you better. Yes using them offhand is not a good idea, at least not for very long. I don't use them attached to a tripod though. What I do is take my spotter, because these still aren't the magnification you need to judge deer, and the spotter is on the tripod. I simply rest my 15x's on my spotter, then drop down to the spotter to judge my animal. This works like no other combo, it's awesome. My understanding, and I may be wrong, is that there is no difference in the optical abilities of EL's vs. SLC's so ergonomics is what you are paying for. I also believe there is no better low-light glass than my 15x56, when looking at long range.
I just picked up a 20-60x85MM Zeiss Diascope to enhance this experience. Now I can judge what I find at those long ranges.
The last piece of the puzzle for me will be a very handy pair of 8x30mm Zeiss Victory or Swaro SLC's for when I am either backpacking scouting or day to day hunting.
If I were you, what I would decide to do first would depend on a few things.
1) What is it like where you hunt. Are you looking miles in the rockies or plains states or are you looking only up to a mile or so. If the former, consider eventually looking at what I'm using. If the latter, then start with a good 10x bino and a spotter.
2) What do you have now. I had a pair of 10x Nikon Monarch bino's and a very decent Bushnell Elite 15-45x spotter. I did not have the 15x's. Now I am, budget willing, filling in the missing pieces.
3) What is your budget. While I love Swarovski's, and think that the EL's are the ultimate. The SLC's in bino's I believe are a much better value. In the spotters, the Zeiss Diascope is comparable to the Swaro 80MM HD, but has an 85MM lens and costs about $500 less and comes with a decent tripod and case, saving you about another $200. For what you could save there you could go buy the 8x30mm SLC's(approx $900). FYI, look at the birding sights for reviews, don't rely on Field and Stream or Outdoor Life.
4) Remember warranties. I eliminated Leica from contention because of their reputation. Now Swaro has an excellent reputation, but their Warranty is not transferrable so if you plan to buy used or sell them someday - beware. Zeiss has a full and transferable warranty, but I don't think their customers service reputation is equal to Swarovski, but I think it would rate an 8/10 to Swarovski's 11/10.
5. Other brands. If you really read others opinions and especially some unbiased reviews I think you will find some other brands that are excellent values. Nikon, Pentax, Minox, and on this site especially Vortex. These are all great glass, but considering things like warranty and resale I still like the top names all other things being equal, so unless I have a compelling reason I will try to buy Swaro or Zeiss in bino's or spotters.
One last pitch for the 15x's. Do a search on here, there is a post where about 10 guys talk about using the 15x's and how it is their go-to glass.
Sorry to be so long winded.
Brian