Trophies are saved on both of your games. Check out the trophy list though. Some of them are pretty special.
What I mean:
Only the host can save the game process, right?
So I want finish Dungeon Siege on the hardest difficulty together with my friend. Maybe within 1-2 weeks.
So we both will get the trophy for finishing Dungeon Siege on hardest difficult? Or only the host?
That is only an example.
I believe everyone gets to keep ALL their trophies they get in co-op games, host or not (at least, that's what I've read in interviews).
yeah but only the host can save the game process, right?
so a friend of me, who never played that game, could join my game in the last act and then he would get the trophy for finishing the game?
Its very important for me. ONly if both player get all trophies, only then I will buy the game.
Yes, he gets it. Saving the Progress doesn't matter. Yours get saved too on the host for when you re-enter.