Hello Ernie,
I have a Kowa TSN-661 w/ a 25x WA/LER eye piece, and a Kowa TSN-821M w/ a 27x LER. I purchased the 661 originally as it was smaller, lighter (thought I might use it for hunting or other stuff), and mainly, it was cheaper than the 821M which was at the time the best scope commonly found on the firing line. From time to time you'd see a Leica Televid show up, but at that time, it was pretty much either Kowa or else some of the older cheap scopes from Champion's Choice. I have one of those too... which does tend to 'color' my opinion regarding 'inexpensive scopes. A lot of people shot HP Rifle for a lot of years with those things... but compared to the 661, I jokingly (only somewhat) refer to it as being on the same level as a cardboard tube with wax paper over the ends. You can see the spotter, but seeing any but the heaviest mirage is a struggle.
When the Kowa 880 series came out, I was hot-to-trot to move up in the world and get a better scope, and one with fluorite lens coatings, as there is a subtle but definite improvement in the ability to see the finer aspects of the mirage with the fluorite (aka 'ED' or 'HD' coatings). That is, until I saw the price tag - at the time they were going for $2800+. Creedmoor sports had 821Ms on closeout for $750 with a cover - which was about what I'd paid for my 661. i about dislocated my arm getting the wallet out fast enough to get one of those ordered before they were gone
Nightforce has a new spotting scope in the works that has *very* good resolution - coaches were able to see .30 cal bullet holes (maybe not all individual holes, but definitely the groups) in the black @ 500yds through mirage during some of our practices @ Raton. I didn't get to look through them a lot, but what I did see looked pretty good. I don't know whether they had any fixed eye pieces planned or not; the model I saw was a variable eyepiece unit. Price is going to be steep... probably in the $3k ballpark.
An awful lot of people have been using the Konus and similar scopes in recent years... Nikon, Pentax, Leica, etc. all make good glass. The big thing with the Kowas (besides good glass) for me has always been the availability of wide angle (WA) and LER (long eye-relief) lenses. I wear glasses *all* the time, and not having to butt my face against the eyepiece to get a full field of view with the 30-31mm eye relief cannot be over valued, in my opinion. Being able to get a full view of your target from a couple inches away is pretty nice as well. The WA part is nice also as it allows you to see several targets to either side, which can sometimes save you some grief if you see that your 'neighbor' two targets over launched a shot wide and right - maybe there is something going on out there that you need to look at more closely!
If you can find a used 661 or 821M (or even a TSN-1, predecessor to the 821), that would be my recommended 'budget' option - best combination of good features, good glass, and good value. Sometimes if you look around, you might find someone who upgraded to a new 883 and wants to sell their old gear at a reasonable price. Sometimes if you put out a 'Want To Buy' ad in the classifieds you may kick one loose where someone was thinking about getting a new scope, but wanted to sell their old one first. Either way works out in your favor
Monte
