Ben Affleck as Batman doesn't bother me. I don't know about his Bruce Wayne. I might buy it if that is after he already figured out who Clark Kent was.
Henry Cavill has it nailed.
Wonder Woman, I have absolutely nothing to go on except for her two non-speaking seconds.
Lex Luthor as the flamboyant eccentric socially-awkward nerd, I'm not buying at ALL. Yes, I liked that line about being psychotic, but... Dude comes across too much as Carrot-Top. Only perfect Lex Luthor IMO has been Clancy Brown and that was animated.
That Sup/Bat exchange when they see WW for the first time made me groan.
That said... I'm still excited to see this.