In reply to UKC Gear:
Good review.
I have the Zelus 25 - this pack's smaller brother - and really like it. However, I too broke one of the compression strap buckles. Again, one side holds, but it did break easily. I phoned Marmot and they said they would replace the entire pack no hassle, but I'm loathe to send it in since I use it so much!
One feature you missed is the rope carrying system, which I assume is the same on the Centaur as the Zelus. At first I didn't think there was one, but they claim there is. Indeed there is one - it's just unusual. If you unclip all 4 compression straps and bring the long ends together you will see they have opposite buckles on. Therefore you can clip them together and cinch a rope vertically down the front of the pack beneath them. It's a little floppy on the 25l but may be better on the 38l pack. Not the world's best rope-carrying system, but it adds no extra weight at all, really. Then again it seems the Centaur also has a rope strap under the lid, which the Zelus lacks due to the zipper opening...