They are similar in the way the feel and fit. They use many of the same parts like the forearm, stock, mag tube, etc.. Trigger groups, receivers, ribs, and chambers are different. The M2 is a tad bit lighter and shorter than the SBE II. The M2 will more than likely cycle the lighter loads better. The SBE's are more geared towards waterfowling. The M2 is Benelli's best all around choice.