I think Jon Snow's stuff during episode 9 last year was pretty good. Brienne vs. prisoner Jaime on the bridge was decent, but not really a proper fight. Bronn's season one trial by combat was pretty good, but more because of how he avoided actually sword fighting his armored opponent. Oberyn vs. Mountain was showy but not really a sword fight since Oberyn was using the spear and he dominated the choreography. So yeah, for the most part it's just kind of average swordplay, with isolated cool moments outside of actual duels (Brienne's horseback stuff this season, Daario vs. rider last season, etc) Like, Brienne vs Hound is a great fight because seeing the characters go at it is awesome, but the fight doesn't really get good until they both lose their swords and it turns into a nasty brawl. The actual swordplay part of the fight was kind of a mess of quick cuts.
The show actually doesn't have much just straight sword fighting in it. Like, outside of what I mentioned and the latest episode, the only other prominent things that come to mind are Jaime vs Ned and Syrio vs kingsguard in season 1? Blackwater didn't really have anything aside from general battle stuff. Robb vs tree in season 2 I guess? Maybe the few seconds of Hound vs Mountain at the joust in s1.
Barriston's just seemed kind of slow to me, probably because the actor was actually doing a lot of the fighting himself since we were seeing his face?