Yeah, the RS5's highs sound natural and realistic. They provide plenty of detail without harshness, they don't make everything sound metallic while still getting cymbals right, they don't sound imprecise and just kind of crappy like a soft dome and of course they blend with the mids perfectly too. And the dispersion seems to work well, it is controlled but the rolloff depends on frequency (correct me if I'm off), so it has some of the properties of a tweeter with a waveguide too.
A vast majority of tweeters just sound off but recently some tweeters have become more refined. I am impressed with the beryllium based drivers I have heard, in fact these are the best transducers on the market right now IMO. TAD uses it to great effect in their proprietary coax driver (probably the best driver on the market period) and it is also used in compression driver diaphragms and some dome tweeters. RAAL's ribbons are also getting to the point where they are sounding good and the plasma tweeters I have heard are spectacular but very high $$$. And some of the electrostat tweets are nice, a friend has a set of ESS Heils that I just rebuilt and they are very good, so are the Enigma Acoustics Sopranino supertweeter demo'd w/ Majicos at RMAF this year.
Louis, have you experimented with using tweeters/super tweeters at the extreme high end? Like 18kHz or so?
I think the supertweeter is a good idea just so you can offer a 4-way single driver based system...
You could have a 20-50 kHz FR system with one driver doing ~500-18 kHz...
Anyway, I am excited to see a BIG Omega speaker... with sound quality, efficiency, dynamics and being able to produce high SPLs they will be playing in the big leagues for sure.