Welcome to the forum.
As Photoshop Express is a Web-based editing application, I would anticipate (I have not used it, but only read of it) that there WILL be differences. As Ps Express is designed for the very casual user, I would guess that some of its capabilities are more related to the consumer program, Photoshop Elements.
However, others, much more familiar with Ps Express, can probably give you something more than guesses and assumptions.
what a stupid answer