Welcome to the forum. I do have some experience with Dynasty and while it was largely not good, that experience is now over 5 years old. I got a good nine years out of my tub, but found their customer service horrible to down right incompetent, but that was 5-10 years ago. The tub was ok insulation wise, I never added any more. I judged this solely by noting we lost power in the winter for 3 days and the tub was still in the 90s when power came back on.