ive had the a7x's for about a month now and absolutely love them...
ive been mixing on KRK rp8s for 8 years, and i must say it is a night and day difference. it went from me saying "man whats wrong with the low mids" to "wow i have alot of stuff to fix and i know exactly what to do..."
i tried to hop on the a7 bandwagon when they came out many times starting from when they came out, and they never had enough low end for me, and just sounded so so bright, in a good way..... but not a way that id like to mix on all day.
for metal bands that are tuned super low, and anything with sub bass (synth stuff mostly) i still click my krk 10" sub on for a few moments to check whats really going on down there.. but seriously in my rather well treated control room, these A7xs go down low enough to the point where id be comfortable never checking with my sub.
as far as the tweeters go, they definitely sound smoother, and less "in your face" to me then the old a7 tweeters, not a bad thing. its like its the same amount of information coming at me, without overpowering. definitely very 3 dimensional. for me it was a toss up between the 8s and 7s too, i opted for the tighter low midbass option, i have a sub and my rokit 8s were flubby and i wanted the polar opposite. im very very happy with my choice
my ONE complaint IS the port noise everyone talks about, if im tracking a band and someone wants it loud its fine, but the one time where it pisses me off is when soloing a kick drum with ALOT of low end, you can always hear the "whoosh" a few MS after the kick hit. it takes a while to used to it.
my settings on the back are low shelf up one click, and high shelf down one click. perfect translation to other systems finally