Ok, I Think I may be the one to help you here,
I was on the 724 AX3's 177cm last season and I am now skiing the 724 EXP in a 177cm.
The EXP's are wider 70mm compared to 74mm in the waist.
The EXP's rip turns harder, feel lighter and are smoother.
Overall my speed across the whole mountain has increased. But this may also have to do with the amount of skiing I have done since last season.
The AX3's and EXP's both perform short turns well, with the EXP's really letting you know if you get in the backseat ------> Zing.
They power through crud, they do not get shoved around, you can lay them on the side and aim up at crud without fear of the tips getting moved.
They have seen some powder but I prefer my v- pros for that, although they get the job done but I prefer to lay it out in big turns for powder.
Oh , and they spin well in the terrain park too.
I might just add that the reason I have the 2005 volkl's is because I actually cracked my AX3's in Whislter over Christmas, they were warrantied wthout fuss. The crack was just in front of the motion binding rail. I still have no idea how the crack got there - ie there was no impact damage or accident that would have made the crack appear.
I am 6 ft 2, 85kg and ski fast, aggresively, everywhere and I do put a lot of emphasis on technique.