I have had my Genesis 5.3 for nearly 2 months and had the dealer's demo pair for about 2 months.
These speakers are flexible (they have adjustments for Tweeter, Midrange and Subwoofer control incl a crossover adjustment). So if you have a difficult room, you can use these adjustments to help smoothen out the response.
Having metal drivers with ribbon tweeters and and active sub, the speakers are fast. So your amp needs to keep up so as not to slow down the flow of music.
Of course if you prefer a more sensual, enveloping sound, by all means this will work too. THe Genesis amps are a definite match and i am evaluating the 360 with Max Headroom (extra power supply).
As it is a dipole designed speaker, you will need space for the speaker to fill the room, if not, it will overload it. My room is 15' W x 18' D and any smaller the speakers will not breath well.
With the active sub, it really works well as bass integration is seamless, unless you crank up the bass and have the wrong crossover point, then it starts to get lumpy.
These speakers can go really loud (provided the amps dont run out of breath) and it can do Swing, Salsa, Rock, big scale classical with no problems are at all...
In terms of speaker placement, Genesis has a set up procedure that is very accurate and once you have Room Lock, the music starts flowing and you stop trying to pick out things to improve (in terms of music flow and presentation).
Read the Genesis Website for the speaker set up. I am sitting about 9' from the speaker and have no issues with driver integration
Have not heard the Avantgardes Grosso so unable to comment.
Good luck in your search.