my 2007 Remington catalog lists the 20 ga. Wingmaster having a 26" barrel as weighing 6 3/4 pounds
That's a misprint.
The Wingmaster 20 with a 26" barrel has been rated 6 1/4 lb. ever since they started making the 20 gauge frame. Same with the Express. That's a pretty accurate number, too. Lift the two guns next to each other.
That said, some people WANT a heavier gun for recoil or swing weight.
The Wingmaster LC 12 Gauge with a 26" barrel is rated 7 lb., same as the 20 Gauge BPS. The BPS 20 will likely kick a good deal less than the 870 in 12, but it will be a bit slower to the shoulder and heavier at the end of the day than the 870 in 20. It's all in what you want.
The fact of the matter is that the BPS is a heavy gun, compared to other major-maker pumpguns currently on the market except for the portly Nova. Do with that what you will. The BPS is also a well-made shotgun, as are the other Japanese Brownings.
My Japanese BT-99, though it works great, has the subtle taint of mass-production about it, that the Belgian guns somehow lack. But so does any Remington, of course, and not so subtle! Wingmasters do get extra care, but at high extra cost for a gun that, frankly, won't do anything that the Express won't do for $400 less.
...so there I go, opining like a gun snob about Belgian vs. Japanese Brownings, but suggesting that an 870 Express is a perfectly adequate shotgun...
Well, those are my opinions, for what they're worth. I'm just comparing the guns in my safe, mostly bought used, or, in the case of the gorgeous Belgian Browning, borrowed. The Express isn't pretty, but it works, and after falling across an old barbed wire fence, the blueing in spots on my prettier polished Remmie isn't so pretty, either.
But as a Browning and Remington owner, I'll have to say, the guns from both companies work quite well.
I'm just illustrating why it's hard to decide, or give really good one-size-fits-all advice, on these things.