The new one is better (Subjective? Sure, and I've only ridden my new one once so far, but it is better for me).
Can't comment on the chainsuck yet on the new one obviously, but it was very bad on the old one.
Personally I prefer the look of the new one too.
Is either worth the money? Only you can decide that, I rode a Genesis Altitude as well and really liked it, but (Again for me) the Hummer is better. Is it 'worth' the extra? That's a personal decision – I say yes.
Are you certain you need an 18"? If you can get away with a 17" I may be able to point you in the right direction for an 'as new' from a shop if you are prepared to wait until Nov/Dec?