@lia I recall a video where Jeff does say that the 5" hub on the street is more squishy feeling, especially if you dial down the pressure for trails. The Pioneer is supposed to be a great off road tire and "ok" on street, but again, worse so on the street with lower pressure. Due to my riding mostly street, I've decided the 5" hub is not for me, but "might" be interested in a 6". :)
I have the GOAT on my GT and the Thundercat on my GTS, but those are both 6.5" AND I ride 90% street, so not a great comparison as I am fully 10% body weight on tire pressure. What I do love about the Thundercat over the GOAT though is that I never feel a transition to the edge, it's just perfectly smooth, like you're riding on a ball, but then no squirrely-ness in the center. The GOAT has an, ever so slight, transition, so I'm definitely not disappointed. Both have really good tread though, which really helps side to side traction on pavement and trails.
You should've visited Sacramento when you were here earlier this year, I could've brought you over to meet Jeff and the TFL guys and you could've tried out all kinds of boards, hubs, tires, VESCs, etc! Next time maybe you can fit that into your plans. :D