Well, I've finally had the chance to test this bag on several trips. Here are my Impressions:

The Good:

• The bag packs quite flat and fits very well into ERJ145 overheads even when fairly full.
• The internal organizaiton is more than sufficient for organizing all my travel gizmos.
• The backpack straps are fairly comfortable and easy to deploy.

The Bad:

• The bag's material isn't nearly as nice as the material used on RedOxx or Bihn bags... or even other Patagonia products. They should make dusters from this material, since it picks up every spec of dust, dirt etc from anyplace you put it.
• The included shoulder strap is worthless.
• I'm not a fan of the plastic D-rings, although they have not failed.
• The materials inside the bag, while lightweight feel very cheap. The inner fabric of the bag loves to get tangled in the zippers.
• The inner zippered compartment has a "lip" which makes packing a clothing bundle into it a bit of a PITA. Also, there are no internal tie-down straps.

Overall, the bag served me well on a dozen domestic trips, all of which have included rides on regional jets... this bag never needed to be checked. However, the overall quality of the bag's materials leaves something to be desired.