Is the Benelli worth twice as much as the Remington?
Hell yes, assuming it's for upland bird use. No question about it. Shoulder the guns. Feel the triggers. Open them up and look inside them (don't cut yourself in the Remington).
Benellis may not be perfect, but the 1187 as currently manufactured is a pig. The 20 is a good deal heavier than a 12 Gauge field gun should be, and that weight isn't distributed well, either. That's not even getting into how they're made and what's inside them.
If you want a 20 Gauge gas gun that won't break the bank, check out the Beretta 3901, if you can find one in 20. Also, look at Franchis, both the 48 (long recoil and very light) and the 720 (gas-operated). My frequent upland hunting partner has a Franchi 620 and a Benelli Montefeltro. They're both great shotguns, easy to carry and great to shoot. I use a 390, 391 or an O/U, and I'm happy with those. I USED to have a Remington... And that was even an old one, when they were built well.
(Note that both of us have acquired these guns over time. We didn't rush out and buy them all at once. Neither must you rush.

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We 20 Gauge fans don't have enough quality choices, but there are a few out there. Remington ain't one.