I have the Konus 20-60-100 and it does a good job. I wanted a Celestron Regal 100mm but got a great price on the Konus so that settled it. Between the Konus and the Celestron Ultima they should be pretty equal.
I had the Konus 20x60-100 as well. Not sure how it compared to the 60-80 but I could see most impacts on paper at 200yds. For NRA high power matches it was fine at too yds.
I used it at Ft Mead 600yd range and I could see the impact markers but of course no individual shots. Also used it at PNTC and I could see impacts on clean steel out to 800yds but I could not provide and impact data on misses at that distance.
I have that Celestron and it worked well for spotting hits and misses on steel out to 500 yards at a recent KD Appleseed. Really good balance of clarity and value.
Just ordered the Atibal 20-60x60, which is half price for Labor Day, to try out.