Bo, I belt modded my NEQ6 because I'd bought it before the AZ version was released. The altitude adjuster on the AZ-EQ6 is worth the extra money if buying new, but for the cost of upgrading? I'm not convinced.
The belt mod is nice, but I don't know for sure if it has improved my EQ6 as I wasn't imaging with it before I modded it.
On my shopping list would probably be
http://eq6wedge.com instead
I guess it just depends on what you want out of it.