Another obstacle that no one has mentioned - we were refused passage through a security/ID screening line at SFO because my bag didn't fit the template they were using. Note, this was the AIRPORT staff, not any airline staff - I have flown with this carry-on for years, and always gate check it for United Express, but never had a problem putting it in the overhead on any domestic and some international flights.
I just bought a new bag, and took a measuring tape with me, to insure it really was only 22" long. I am tired of the hassle of dragging the bigger bag around.
Kate