The Star Wars Identities exhibit was fantastic. I highly recommend if you are spending time in Montreal to check it out. Just make sure that you book your tickets in advance since this exhibit is very popular and was sold out the day that we went.
The ticket for Star Wars also includes the other exhibits that are being held at the Science center so it is definitely worth the price of admission. You will probably spend an hour to an hour and a half with the Star Wars exhibit. Don't feel rushed while going through the exhibit and admire all the awesome artificats (including original drawings of the Star Wars movies and characters). I think I took over a hundred photos, so make sure taht you bring 32gig SD card to take as many pictures as you can. Highly recommend!
Cheers!