Love the Super Ego and the Zephyr but...
For what its worth...
My wife and I discovered Tom Bihn last year and have spent enough on bags to put someone's child through college at TB. I have a Super Ego, my wife the ID and Zephyr. Not to mention a lot of accessories. I also have an Aeronaut-I think I got the last purple one.
I love the SE, but not so fond of the flap arrangement and the fact that the bag tends to fall over. The Zephyr seems to be the logical next bag, but I do really like the bottle holders on both sides. The Zephyr has no such thing. I would really like to see the Zephyr's successor with two bottle holders like the SE, but have the strap connections on the same side of the bag. The Zephyr isn't as comfortable with heavy loads as the SE due to the alternating strap connections on the bag. Picky perhaps, but simply a suggestion.
I don't know if its a matter of fabric colors, but I liked the unusual and bright colors. Colors that set your luggage and bags apart so they are easier to see in a group, etc. Please update your website as well. Often I've noted the color choices listed are no longer made.
Having said all of that, keep up the fantastic work. TB products are by far the best I've seen on the market and your customer service should be taught in business classes as a model for other companies.