Gregory Savant and Z series?

So I've been looking for a new pack for 2-5 day hikes. I recently found through work I get a killer discount on Gregory packs. Cool, however due to there cost I really haven't looked at them before. I'm looking for a light back +/- 50L. I'm 6'2" and looking to carry 30-40 lbs of gear. Less in the future. Do any of you have first hand experience with the below packs?

- z55 or z45
- Savant 48 or 58

Any other Gregory input or experience would be great too.

I've alternated using the Savant 58 and Z55 all summer. Both work great, but luckily the fixed suspension fits me. Both were comfortable with 20 to 25 pounds in them. I'd highly recommend either - but take your gear to the store (all 30 - 40 pounds of it), and load it into the packs to get a feel for them. I might opt for the Z Pack, simply because they had a slightly beefier suspension.