Updated in January 2021
I do not look at spotting scopes as much as I used to, but I do keep an eye out.
To be honest, high end spotters is not where most of the interesting things in this market happen. I do not think you can find a bad spotter in this price range, although I have seen some spotty stuff from Optolyth and a couple of others.
That having been said, my personal take on spotters has changed somewhat since this was last updated. I am a shooter, not a birder, so my personal preferences lean very strongly toward spotters that either have reticles in them or have reticle eyepieces available. While I will not restrict this to reticle only spotters, it is a part of the conversation.
Personally, I would not be buying an ultra fancy spotter with my own money. However, there are a few interesting things happening out there which merit noting.
The best currently available spotter for shooters is probably Hensoldt Spotter 45 (or spotter 60, if a simpler reticle with a little more magnification works better for you).
I used Swarovski STR80 20-60x with MRAD reticle for several years and I can comfortably recommend it. It is a really exceptional design and I can comfortably recommend it. However, the Hensoldt has better depth of field which really matters for looking at wind and watching bullet trace. They cost about the same though and Swarovski is a little more compact.
85mm Vortex Razor is up there, but costs less. It is not as good as the more expensive stuff, but given the cost, it is a very appealing option. For me, it would definitely be in the running, now that there is a 22x reticle eyepiece for it. There other fixed power eyepiece is a LER wide angle design and it was absolutely excellent when I tested it. The reticle eyepiece is pretty much the same thing except with a reticle.
Where there is some differentiation is with different features: reticles, modular systems, etc.
With modular systems, two stand out: Kowa Prominar 500mm and Swarovski ATX.
If you are primarily interested in prolonged observation and have money to spend, I think Swarovski overall edged ahead of the curve. Their ATX, STX, BTX spotter setup is really nicely done. Essentially, they have objective lens modules and eyepiece/prism modules that all interchangeable. The objectives come with 65mm, 85mm, 95m and 115mm diameters and they are all excellent. The eyepieces are angled, straight and dual angled for binocular vision. I do not like the divorce-inducing pricetag, but it is a brilliant design.
If your primary need is to also use it is a telephoto lens with your DSLR or mirrorless camera and that can also take a traditional spotting scope eyepiece, I think Kowa Prominar 500m lens/spotter system is an excellent solution.
Both Swarovski and Kowa do this very well.
If you want a more traditional spotter, it is hard to bet against Kowa’s 88mm Prominar. Their 55mm Prominar is head and shoulders the best compact spotter I have ever seen. If I could get a reticle eyepiece for it, I would own one already.
Meopta S2 25-70x spotter is pretty much alpha level optical quality for a bit less (though still a lot) of money.
Personally, since my use of spotters is somewhat less frequent now, I have mostly switched to mid-range designs that have become very competent. At some point, I will get into the $2k+ range again, I am sure.