One isn't better than the other just different. The real difference is the person setting up the captive environment. The care and attention to variables the keeper does makes an a snake thrive not the enclosure. A tub doesn't help one bit in the hands of a ignorant uncaring keeper it doesn't magically make things better.
I am not going to disagree but I am also not agreeing. I have a rack and enclosures and tanks i switched from a tub some time ago. Every ball python is thriving in all. Actually as I think on it the breeding season hunger striking snakes are in only the rack. Not sure if that means anything or not even, though the oldest male (24 or so) is in a enclosure. I found that the single tub was by far the hardest to maintain a proper gradient, I had a hot spot and then a cool spot no gradient at all. My enclosures step a single degree every 1.5 inches or so, gradient. My rack has a hot spot that drops 3 degrees every 1 inch not a real gradient, just a hot spot and cool spot. I don't have issues with humidity in any of mine I just have differing problems that require different solutions. Tubs need careful ventilation as they can become a breeding ground really easily for nastys. (warm high humidity with low airflow)