I've had my ultimate for ~a month now. It's replacing a chrome metropolis, which i rode with for ~5 years (still in pretty good shape- anyone interested?).

I agree with most of what folks have been saying here- the pac is huge, with almost 2X the working capacity of the chrome. Fewer little pockets to organize stuff, no really good place to put pens. All the straps can be pretty confusing at first, although the velcro patches help keep things organized.

The pac fits me much better- i'm scrawny, with narrow shoulders, and the chrome had a tendency to creep off my shoulder if it was empty or really full.

The x-strap rocks- 95% of the functionality of a backpack, once you figure out how to adjust the straps.

One i didn't think i would like, but actually find really useful for large loads is the waist strap. Like the waist strap on hiking packs, it shifts a good portion of heavy loads off your back onto your hips.