To answer your question about Vmax vs. Vstar, I think of them like a branching evolution like Politoed/Poliwrath. Not all pokemon have both, but some like Charizard do. Vmax pokemon tend to have more HP and are worth 3 prize cards while Vstar pokemon are worth 2 prize cards and have a "Vstar Power" which can be used only once per game and have powerful effects. For example, Dialga Vstar lets you skip your opponent's next turn. Both cards are stage 1 since Pokemon V are basic.
To answer your question about Vmax vs. Vstar, I think of them like a branching evolution like Politoed/Poliwrath. Not all pokemon have both, but some like Charizard do. Vmax pokemon tend to have more HP and are worth 3 prize cards while Vstar pokemon are worth 2 prize cards and have a "Vstar Power" which can be used only once per game and have powerful effects. For example, Dialga Vstar lets you skip your opponent's next turn. Both cards are stage 1 since Pokemon V are basic.
Awesome, thank you for the detailed explanation! I wonder what the determining factor is for getting a vstar form is? Just popularity?