A good pump gun ...is a good long term choice, in my opinion, and no matter where you go with this hobby, of shotguns, you'll probably always want a good reliable pump gun maybe in both a 12ga and a 20ga around.
Personally, I like the Browning BPS Hunter model a lot more than the 870 Express ...or even the Wingmaster / but in my mind the Wingmaster and the BPS Hunter model are on the same level in terms of quality - but nothing wrong with the 870 express model either...
Even the best pump guns ....if you put 500,000 shells thru them will exhibit some wear on internal components .....but to most of us, at least in a pump gun, that's a lot of shooting. Most of us turned away from pump guns - in favor of O/U's for competition or clays shooting ...but when I was younger, I shot my BPS Hunter model with a 28" barrel for a long time at Trap / even doubles - and a lot of live birds. I still have the BPS's I bought in the late 70's ...still solid guns ( in 12ga and 20ga)...and they've survived a couple of boys - and a lot of grandkids since - and many shooters will tell you the same story about their 870 Wingmasters or model 12 Winchesters.