The one residual concern with ribbon tweeters is comments like this...
I've yet to meet a ribbon tweeter that does not require your head to be in a vice to really maintain the sweet spot.
... basically very little dispersion, particularly vertically.
Probably not an issue with bookshelf speakers where raising & lowering to match your ears is as simple as changing stands (the tops of my M5HPs are somewhere around 47.5" off the ground) but more of a challenge for towers where you need to get into raising the front legs & tilting them back.
