shot one last year with 1 1/8 oz target loads. it was a 28" ported with modified choke tube. I didn't notice any significant reduction in muzzle climb, and the noise was noticeably louder, though not extreme. I shot the same loads in a Rem 870 28" modified choke barrel for comparison. It might only be the difference in the guns, but I prefer the 870. Like the Mossy-- like the 870 more. Don't really care for the ports.
Compared the same barrels and loads over a chronograph, and the non-ported 28" 870 barrel consistently shot 50 fps faster. I didn't notice a significant difference in recoil, either.
HTH...