I've got the newer 60L. Overall, I'm very happy with it. I removed the aluminum stay to make it lighter and more comfortable. The straps are useful for really dialing in the load. However, I did get a small tear in the pack fabric near one of the strap points from cranking the compression too tight, though.
My biggest complaint is that the shoulder strap material is not bonded to the padding inside the strap -- the cover material slips around, causing the load lifters and sternum straps to shift into uncomfortable positions along the strap.
I placed a couple of strategic stitches, but they aren't strong enough to hold the material in place. I think I'll get a couple of bartacks thrown on there to hold it down. In the meantime, I'm constantly readjusting the fabric to get it back in place.
Also, the zippers on the lid seem kinda cheap -- the metal zipper pulls have already broken off. Luckily, the zipper itself is still OK, I just threaded some shoelace material through the zipper head to replace the missing pulls.
Overall, a great pack -- super lightweight and adjustable.