Being a glass man myself I think it all depends on your meaning of the "Best".
If you mean most efficient, then tubs can be depending on your set up, number of snakes and application, (EG breeding or not). They can also be most cost effective.
However, if your sole purpose for owning a snake is to have a pet snake, as is mine. Then a glass viv is the way to go, you can see the snake easier, the viv is prettier, you can watch your snake without popping the top off. Glass vivs require less in the way of customizing, and most of the things you need for it can be readily obtained premade. Cons of course are cost. A basic glass viv will run you no less than $30 new, a Tub can be had for less than $10.
Just my thoughts, mind you I've never used tubs for my snakes, and switched my mice to glass tanks shortly after I began breeding them.