I would use "was".
Can this be said:
My friend watched The Avengers 2 in 4D and he said it is/was totally worth it.
Are both okay? What would a native english speaker say?
Was because his friend watched?
I would use "was" if I were talking about my own past experience.
On the other hand, if you know the person you are talking to is thinking about going to see the movie, you could use "is" to refer to their future ticket purchase.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.