I own (and reviewed) the Aquilas and the suggestions and opinions on this thread are all correct. If your room is larger, then you will likely be much more able to justify the price difference and take advantage of what the Altair can do than if you have a much smaller room. That said, Andy has informed me that even in my smaller room (14' x 18' x 8') that the Altair will still work well.
Cmalak pretty much sume up my opinion of the Aquilas.
One thing I would note though - in my opinion you need enough power to drive the Aquilas if you listen at any reasonably loud volumes. I have Lamm 1.2 Reference monos (which are, like the Vitus, solid state amps that are conservatively rated at 115 watts per channel Class A) and they are fine driving the Aquilas. I am not so sure though if the Vitus at 50 watts would do as well. The Altair is more efficient and a bit easier to drive.
Good luck in your search and, if you do end up with Rockports, I'll bet good money you'll be happy no matter which one you choose. You rarely see these speakers up for sale for good reason.