If you can afford the best you have several options available to you, all of them very good.
In this price range, all products you will find are superb and a lot really depends on you personal preferences.
In terms of ability to see detail, I think Kowa Prominar with 88mm objective lens is the best there is. It will run in the neighborhood of $3k.
Just behind it a several spotters from the “alpha” makers:
82mm Leica Televid HD
80mm Swarovski TM/STM High Definition
85mm Zeiss Diascope FL
Generally, with top end scope ability to see detail roughly tracks the objective lens diameter, with Zeiss offering slightly better centerfield resolution than Leica and Swaro. However, differences are truly minute and, I think, Kowa still resolves better than all three.
However, the image through the Leica “pops” a little more due to higher contrast (traditional Leica trademark).
Keep in mind that eyepiece choice is very important with a number of fixed and variable options available for all of the above.
If you want a smaller premium spotting scope, all of these makers make smaller models as well, with my favourite being Zeiss Diascope 65mm. Once again, all of the “alpha” makers have spotters of comparable quality with 65mm objectives, but I like the fact that Zeiss eyepieces go down to 15x. It comes in handy in low light.
Finally, if your applications lean a bit more toward the tactical end and you are willing to spend $5k, check out Hensoldt Spotter 60. It is a 20-60×72 spotter of the Folded LightPath (FLP) variety. It has an illuminated ranging reticle and absolutely stunning image quality. It suffers a little bit in low light compared to larger scopes like the 88mm Kowa, but on the plus side it has better depth of field that almost any othe rspotter I have mentioned. That makes it work remarkably well for bullet tracing and also simplifies looking for distant objects.