Well I cannot tell you how awesome the 20GA was! I put about 50 rounds of the birdshot through it and would have gone more but I blew up all of our targets.
Loved it, easy shooting, light recoil and fun as hell. Mine has the long barrel on it (28") now, and I want to get the extended mag that will allow 9 + 1. I am open to trying shorter barrels and also want to put some heavier shot through it just to measure the damage and feel of shooting it with buckshot or slugs.
The most important thing when taking your GF/wife/kids or newbie shooting friends is that it is fun for them and they enjoy it. this will make for repeat shooting trips and make them an enthusiast as well. We have all seen the videos where someone shoots and it knocks them on their rear, well while funny to some to watch, probably not going to make them a fan of shooting if they can't move their arm for a week.
You can get a good 20GA for relatively cheap, perhaps a his and hers is in your future? I know I am way more into the shooting hobby if I am responsible for my own gun, cleaning, learning how it works and best of all shooting it!