We are dedicated carry on peeps, play by the rules, check the equipment used on the flight since certain airplanes have smaller overheads (MD80's for example). I have a closet full of suitcases and use the most suitable (pun intended) for the flights. Doing a trip on Delta a few years ago to KS to visit family we were gate checked with 2 very small carry on since our inbound flight to Atlanta was delayed and the flight was full. No problem until the ramp rats overloaded the elevator to the jet way so we could retrieve said legal carry on, temp was around 40, jackets in carry on, we were locked in the unheated jetway until they cleared the jammed elevator, almost missed our connection, were treated like idiots. Got to the connection gate and all overheads were full so got gate checked again. There is nothing wrong with carryon as long as the rules are enforced from both sides.