This is the only Tumi Alpha Carry-on that meets both the 22x14x9" and the 45 linear inch limits used by most domestic airline. For many years, Tumi advertised their bags by the internal dimensions while the airlines go by external dimensions. They have recently updated the Tumi site to show the external dimensions as airlines get tougher with carry-on restrictions and customers return bags that get force checked. While the airlines will usually let you board with larger bags, you never know when you might be forced to check them. This bag holds almost as much as my old Alpha 22922 and makes for much less stressful boardings. Note that the Tumi Alpha "Continental" which is often pushed as a legal alternative is wider than the max allowed by many airlines and also exceeds the 45" L+W+D limit of others.
My only complaint with this model is that it does not include hangers. Tumi does sell a nice set on their site, but at this price I would expect them to be included. Some have complained of the handle sticking on this bag. This can happen with any of the Tumi Alphas that I have owned, but is easily overcome by starting the downward movement with a gentle tap with the palm of my hand rather than a steady push.
Update: Since writing this review, I've been in line with several people who have been force-checked with slightly larger bags. They usually argue that they have "always been allowed to carry them on before" but get no sympathy from the airline employees. This bag has always gotten through without a problem. Watching their bags hauled away reassures me that my decision to replace my old Tumi with this model was a good one.