Taking a closer look at the entire Q line, a few things become obvious.
A) They all use the same tweeter/midrange
B) All of the drivers come from the same family of design
C) All cabinets are of the same rigid aluminum construction
D) Crossover parts are all the same
E) Aside from the Q1, they are all four way designs
So the only differences will be the size of the mid-bass driver and the size of the pair of the woofers.
What this means, practically speaking, is that the entire Q line should sound the same with the exception of total linearity in the bass. Bigger drivers = more efficient coupling with the room they are in = greater dynamic linearity = the ability to play louder without any sense of strain.
I would be very doubtful that, for instance, the Q5 and Q7 sound much different given a sound level that didn't push the Q5 to it's limits. (assuming the same associated equipment and room size) If they did sound much different, I would be either very wary of their design or vary wary of the validity of the listener's abilities.
Also, in the endless arguments over the various big time speakers, the most fundamental differences are so often overlooked!
Magico=Carbon Fiber drivers
YG=Aluminum drivers
Wilson=some sort of ridgid phenolic
Evolution Acoustic=Ceramic
THIS singular point is going to be THE overriding quality that dictates their sound. Not so much cabinet construction and what not. (They are all sufficiently herculean in that regard.)
To me, the EA sound great but with an obvious ceramic quality. The YG can sound pretty decent, but with an obvious aluminum quality, and so on and so forth.
Nothing more than design choices. Nothing more than flavors.
So the arguments over which is higher "Fidelity" is pointless.
(though the EA does have arguments in this area, but for different reasons and ones that are masked by the ceramic colorations. different topic, different thread)