Out of all the Remmy's I've had, although the Express is similar, the action has nowhere near the smoothness of the Wingmaster.
Sure, functionality and construction is essentially the same but go to the gunshop and try both.
(If you're working with a budget...the Express will do the same thing. It's quality and construction is the same as the WM)
If you're don't have a budget...there's no question...Wingmaster.
IMO, there is no pump shotgun that has the smoothness of a Wingmaster.