Hey, got some more questions about your shotty. I think I have the same model as yours, the 870 Express, 7+1....got that $hitty bead sight on the pedestal that's impossible to swap for a fibre optic. Mine also didn't come with rails to mount any optics, but I see yours has rails. My undestanding is that only the Tactical came with rails, so did yours come with rails, or did you mount the rails yourself? Factory Remington rails or aftermarket?
I almost bought the Bushnell TRS 25 this weekend as well (on sale from Cabela's for $79.99), but figured I should probably mount a rail first, haha! It looks like it's got some great reviews, plus it's waterproof and it holds up to shotgun abuse. Way more affordable than the Aimpoint Micro series.