Swaros are excellent, especially the larger ones, if you can afford the price and the heft. These puppies are huge and heavy.
The larger the objective lens the greater the resolution capability, and that's where the Swaros shine. If you need to see the back side of a fly at 2000 yards, get the biggest Swaro possible, and a mule to carry it.
I use my Kowa from position on the line to observe the conditions, watch the flags, and poach on other targets, of course. When I got my latest unit, it was a decision between the 88x and the 99x. The 88x won because while it was a big unit, it was still manageable on the line and allowed me to discern the faintest wisp of mirage while still provide excellent IQ.
What I like about the Kowa brand, after their use of CaF2 lenses, is the wide panoply of eyepieces, digiscoping adapters and other accessories. Swarovski also has a large assorment of eyepieces and accessories.
If you're going to get a quality spotting scope, I would suggest strongly that in your list of specs you have "interchangeable eyepieces." This capability multiplies the uses of the spotter dramatically.
For instance, for my Kowa, I have a 25-60X zoom eyepiece, the 25X LER eyepiece (no longer used,) and the phenomenal 80 degree wide angle eyepiece. I also got the astronomical unit adapter and bought a 3rd party astonomical eyepiece that further extends the capabilities. Looking at the Moon with that combo is amazing. I also have the digiscoping adapters and did a video with my Nikon D-7500 on the Kowa 883 at Ben Avery year before last.
You can view it here.
There are many fine spotting scopes and it would be a good thing to figure out what your needs are before jumping in.
EDIT: There seems to be some issue with viewing the video through NikonImageSpace.
Here is a link to an entry on my Facebook page that has the video.