I have looked at the Contrail. On paper, it's the same size as the Ozone, not too much heavier, and I like the double handle. The price puts it completely out of range for me. It's a shame, because it looks like the extra $$ is partly because of the two extra pieces that come with it, the 'Flight Locker' ($49 by itself) and a laundry bag.

I'm pretty sure the Ozone measurements are the actual outside dimensions. The capacity is 46L, but I'm skeptical. I think the measurements are the external frame (good for sizer), and that the volume is based on those measurements, not on the actual internal volume. If I am right, that might be a deal breaker.

As I noted above, my current aging go-to almost-indestructible wheelie is a solid 22x14x9 minus a couple small wheel protrusions and handle rails inside. It's 1/2" too tall for a sizer, but it definitely holds more than the Porter 46 - there are times I've taken it because the Porter was just a bit too tight.

Have you looked at the Osprey Shuttle? It actually looks very much like the Porter on wheels.

Here's an interesting (drive you crazy) comparison: Shuttle and Ozone have the same dimensions (22x14x9), but the volume of the Shuttle is 2440 and the volume of the Ozone is 2807. Grrr.

Another thing to keep in mind (may or may not be relevant - depends how you travel and how hard you are on your bag). The Ozone has the newer 'high' carriage wheels; the Shuttle and Contrail have more traditional rollaboard wheels. The Ozone is designed to be better on 'rough' terrain.

One final point: REI has a 20% coupon for a single item right now, so if you are looking at any of these bags (or similar), it's a good time to shop REI.

I'm going to have to take a tape measure and do some actual measuring at the store.