Piggy-backing on the comments re: pump action.
I think if one goes with an expensive dual-action shotgun -- both semi and pump in one firearm -- you can have the best of both worlds.
If, however, money is an issue, that's not going to be the best option.
For pump action, I like the Mossberg 590 I posted. Mossberg's actions have been engineered to provide a uniquely reliable method of chambering a round. It also offers an excellent way to load directly into the chamber if the tube is empty.
I also have a KELTEC KSG that holds 14+1 and is a bullpup design. If you're looking for home defense shotguns, don't overlook the bullpups.
The KSG is excellent for close quarters. No long barrel sticking out, and a pistol grip for the trigger hand. The biggest disadvantage is the need to practice more until you get the pump action mastered. People regularly complain they short-stroke it. That's because the length of pull is so much shorter than a full size shotgun. Instead of having the support hand extended to the fore grip, allowing a long, smooth pull to rack a shell, your support arm starts on the KSG with it bent at the elbow and pointing more in a downward direction. You have to seriously manhandle the gun when racking another round since you don't have the same leverage.
The KSG design requires the carriage to move past the end of the magazine tubes inside the butt stock before it can grab the next shell. If you only pull back far enough to eject the expended shell, it's not going to pick up the next one, requiring yet another pump to load a round.
There are all kinds of reviews of the KSG. If interested, I'd watch them first and commit to practicing if you decide to get one. Even if you use dummy shells to just practice cycling the action, you'll be doing yourself a huge favor.
For first timers, I think a "standard" size pump action is better if for home defense. Having the Mossberg and the KSG gives me options.
Don't get me wrong. I love the KSG, and I won't hesitate to grab it from the safe if needed. I'm just saying you should know what you're getting before making a choice.