It is actually a few pounds lighter, you might have got mixed up with the shipping weight. Only the 4308 and above are heavier than the Z7.
The Z7 no doubt has better specs overall especially if the unit will only be used as a prepro. I suggested the Denon as an alternative due to its lower street price, and the fact that some people (me included) must have Audyssey. At <$1000 the 4310 is just hard to beat.
The weight is funny. Amazon states one thing, One Call another, and Denon website yet another.
I thought the Audioholics review painted a better pre-pro picture for the Denon, but the score card as a whole leaned towards the Z7.
As far as Audyssey, I feel both of my Yamies auto calibration were far more thorough than my friends 3310. I see the need for the support for the Audyssey company technology, but I honestly don't see the need for it to be the deciding factor for a purchase.(certainly not for me)
I actually don't like his 3310 at all, not to mention the joke of a manual. And paired with his more efficient 8ohm B&W(683/685/HTM61) speakers in a much smaller room, it in no way compares to my system.
EDIT: Not meant to sound flaming.
