I just bought this model. I did have a 870 express for several years. I will say that they need to have 100 shells of bird shot ran down the bore to smooth out the action bars.
When I sold my 870 express it might have had 500 rounds of mixed shells cycled out.
The action was so smooth that you could cycle it with only a a few fingers on the fore grip.
The 870P that I bought has a much nicer finish to it there's no sharp edges on the mag well or the ejection port. My express model had a few rough edges.
My police model is pretty tight right now and reguires a firm grip on the fore grip I can't wait to hand it to my 4 ons and have them dump plenty of rouds down range to smooth it's action for me!