I can't say I have much trigger time with the 870, but my 500 has been putting birds in the freezer for the last 20 years without a hiccup.
A little loose fitting in the forearm maybe, but think of them more as the AK-47 of shotguns !
Also have a short barrelled Winchester 2200 as my primary grouse gun, but the 500 is still more reliable IMO.