despite what people would have you believe, there is no functional difference between an 870 Express, Wingmaster, Police, or even a DA Grizzly.
Wingmasters are polished and gloss blued, Expresses are rougher machined and matte blued, Police are parkerized and supposedly built in a separate part of the plant with tighter quality control, Grizzlies are made in China by evil communist child labourers.
none of them have failed to go BANG so far. the Wingmasters and Police are smoother but they will ALL break in and smooth up over time.
the Grizzly posted is from the very first batch - they are slightly rougher now, but still better than an Express.
as ive said before, think of the 870 Express/Grizzly as Craftsman or Mastercraft wrenches, and Wingmaster/Police as SnapOn. if you want to pay the extra premium for something better finished and with more pride of ownership, then by all means.
either will remove bolts just fine.
as for people b*tching about the decline in quality of Remington, Marlin, etc - it happens. people want cheap guns, and noone can afford to pay for unionized American labourers to hand-fit and inspect parts anymore like they did in the 50s. the internet makes it possible for people to ##### and have their cries reach the ears of the entire world.
if you like the 870s, just buy whichever fits your fancy/budget. its a rock solid design, everything on them can easily be replaced/fixed/customized.