I like this carry on bag.  It has 4 wheels instead of two.  And you can pack it pretty good.  It has the ability to expand if needed, but only by maybe about a 1/2 inch.  It has nice containers within the pack that allows you to separate the smaller things like passports, and other items in it.  It has a handle that expands and closes.  This bag is the correct size to fit in an overhead compartment with no problems.