SBE's are great if you have the need for shooting 3 1/2" shells for geese or turkey but nothing else, plus its an extra $300 or so than the M1.
I have an M1 and love it. Consider getting the M1 in black synthetic stock but get the Rifled Deer model and then get a 26" bird barrel so you can switch up when you need to for dove, geese, duck, turkey etc... The season is right around the corner and if your looking save some cash on an extra barrel or forend or anything benelli, I would try ebay and gunbroker.com for some stuff. You will absolutely save mucho dinero $$ than buying brand new barrels from a dealer. Just trying to help! Good luck!