How modded is your 870. I'm a dedicated anti-mossberg kinda guy but i'd jump on a chance to trade an entry level 870 for a 590. The military versions had lots of upgrades and honestly the action release is in an easier to access location. The safety is my main stigma on the Mossy's...that and their general lack of quality..they just feel creaky i dunno. I'd go for it tho as the 590 is top of the line in mossy pump gun.
just the opinion of one Moss hater
just the opinion of one Moss hater