For strictly in-home defense at <15-20 yards, I think one could have a very capable sub 20 yard HD 870 for under $700 if you find components on sale, or $900 if you add an optic.
$275 for preowned 18" 870P or Wingmaster with bead sight. (Using Oregon45's price)
Vang Big Dome safety ($15).
Suggested adds, but would have to be added to the Beretta too.
-proper LOP ($110 Magpul SGA)
-forend with WML mount ($60 FAB Mako or Magpul)
-WML ($100 Streamlight TLR-1/Inforce)
-Side Saddle ($80?)
Long gun holster:
A forward sling mount ($25, Magpul)
Blue Force Gear sling ($50)
Optional, but significantly improves range.
Red dot. ($150, Primary Arms Advanced Micro)
Scope mount rail ($50?)
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The Beretta 1301 starts at $850
Add $325 in Aridus parts and another $110 for Magpul stock
$100 for a WML
Same price for the sling setup
Aridus side saddle $150
Optional $150 PA red dot and $125 for Aridus CROM
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I think the 870 still wins on price.
For the civilian defender, the ability to simply swap in a 28" hunting barrel might be attractive feature.
The 1301 is more refined, absorbs some of the recoil and can't be short stroked.