I've heard the Aquila a few times at Goodwin's in Boston. It was a while ago but I remember the huge deep soundstage and ability for this speaker to bring the venue to the room.
Many speakers bring some of the venue to you but I felt like I was at an AC/DC concert, or in a concert hall. Great ability to pressurize the room if that makes sense.
If you are serious about laying out the shillings you should fly somewhere to listen to them. The thing with Goodwin's is that they have such a selection you just might change directions too.
Never heard the Altair so sorry if this was not what you were looking for.