Most any pump shotgun, even cheap Chinese guns will serve well as a home defense gun.
However, going on what is the "best"........
A key to durability, reliability. longevity, and being able to stand up to the Night Watch version of "Hold my beer and watch this" is that no shotgun design made since 1950 can beat the Remington 870P Police shotgun.
Still today, something like 95% of all law enforcement; local, state, and federal all use the 870P Police gun.
This is not because the gun is cheaper or that departments get a better price then other makes, they don't.
It's not possible to make a forged and milled steel gun with heavy duty internals as cheap as you can make a cast aluminum and stamped internals gun.
This is the reason the Mossberg 590 won the government contract. No matter what, they were going to get the contract because they could make the gun cheaper then Remington could.
Nothing in the contract was a test to find the "best" gun, it was simply that if your gun could pass a basic test you could bid on the contract.
Since almost any shotgun could pass the test and could submit a bid, Mossberg was going to get it.
The 870P Police is the pump gun that all others are judged by and few equal.
As example, really heavy shotgun shooters who shoot clay birds will tell you that an aluminum pump gun will start to develop cracks in the receiver and begin having broken parts somewhere less then 70,000 rounds.
The 870 will begin developing cracks around the ejection port somewhere around 250,000 rounds.
So, if you really want the best and can afford it, buy a Remington Police model.