Ditto, what they said, plus...
You mentioned you cook for a family of 4. Do you ever entertain, have friends or family over, or intend to cook for outings/work/picnics, etc? My point is the 3 gives you
options! It will work fine, for the 3 smokes you stated, but what if you want/need to do more at one time? Believe me, the capacity cannot be replaced by any other manufacturer. That 20" depth is amazingly flexible, from full, uncut packer briskets to multiple butts. I love it!
As for the jerky dryer: Great investment. You cannot do jerky or sausage in these smokers (too moist of an environment) without moving the air through it (like a dehydrator). The advantage to this is that you smoke, and then dry, the meat in the same place! You keep it in that smoky place, and don't have to transfer to a dehydrator. Lazy Q, man!
Can't beat the taste, either! Much better than a dehydrator.