Great report, Pete! I appreciate you taking the time to 'vet' those sites for us. Your hard work showed, and I learned some things I didn't know before.
I'm also a big Southwest fan. One thing I don't see mentioned too much are the Southwest Youth fares. You have to call for these, but they are typically offered at a nice discount off the "Anytime" fare. They come in handy if your plans change too close to your trip, so that the lower "Wanna Get Away" fares are no longer available. They are also treated as an "Anytime" fare, which means they're refundable (better than just a credit to your account), and you can make same-day changes without worrying about paying a different fare.
Here's an example: A couple of my kids are active in sports, and attend tournaments all around the country. You never know in advance how long they're going to be away; if they're winning, they keep playing and if they lose they come home. So we have to guess when we make our original flight plans.
When we use Southwest, we'll often book using the lower Wanna Get Away fares. Then if junior loses early I can just call up, cancel his original flight and rebook him on an earlier one. I don't have to pay a change fee (typically $100 on other airlines), but I do have to pay the difference in the ticket price (which I'm fine with). With the youth fares, that difference is substantially less than what it would be for a regular fare.
On another airline, I'd have to pay the change fee ($100) PLUS the fare difference -- with no youth discount.