I have heard both the Olympica III and Olympica Nova III in the same room but many months apart and on different gear.
I heard the Olympica III and thought they were nice. Balanced but not sure they were an all out upgrade from my Thiel 2.4s. Then I had a breath in counter with the Olympica Nova 3 on the new Classe amp and pre. I thought they fell into the outstanding category. I would say they have a little bloom the in the bass, are very flat until about 8k-ish then I felt they had a little rise in the treble. This was with pretty heavy toe in so more straight would have made the highs flatter. I felt like the mids were pretty flat, not dipped down like older Sonus sabers.
For me this speaker is on pare with the Wilson Sabrina. I feel like the Sonus faber is a little softer in the leading edge of the bass and the wilson hits a hair harder with the leading edge impact but this was different dealers so take that comment for what it is...
here is a good video comparing the two. I would check out their other videos too. One of the better audio channels. I really like the looks of the nova but would take a used Olympica in a heartbeat. If I did not think my kids would destroy them (no grills!?!) I would own them.
https://youtu.be/Xv8dvVIdguk