Ah, agree or disagree, it's illuminating as always Jim.
Let me add that I don't think it's necessary to pay off the mortgage either. In fact, since they're in their 30's and apparently doing well enough, I agree that there's no reason to....
On the other hand, paying off the mortgage early can also be considered as a very conservative form of investing.... One that may be more practical to the monthly budget for a family with 4 kids and a combined 50k income....
Still, I would agree that if the monthly budget isn't too tight, investing is most likely the better route.
I also agree that dividend in a taxable account isn't a big deal either, especially since they're still in a low income tax bracket.... However, I'm anal about paying more taxes than need be.
So, if there's any way to avoid that, I would... especially if the passive income is no longer needed.