I have not heard the Altair, but I have heard two other Rockport speakers, the Antares (an incredible full range speaker, and my personal favorite), and the Mira Grand (a incredible almost full ranges speaker, only missing the lower half an octave). Both are excellent speakers, and if I could afford either, I would gladly buy either one.
My opinion is if you can afford the Altair, and want to have speakers from one of the premier speaker manufacturers in the world, you should take the time to go and listen.
My opinion is if you can afford the Altair, and want to have speakers from one of the premier speaker manufacturers in the world, you should take the time to go and listen.