I had the SpaceOAR insertion at Mayo Rochester (late Jan 2020). I didn't particularly feel any discomfort during or after.
I live in a small community (about 100,000) and I was surprised to hear from a fellow PCa guy that he was told that SpaceOar is only done quarterly in our community when the two urologists get enough patients and a rep from the SpaceOAR company can come. Since I think these urologists are competent it was surprising to think they had to wait for a company rep to come. May speak to the benefits of getting treatment in a facility that does enough SpaceOAR insertions to not need/want a company rep to be present...