This was an excellent and humorous movie that was well acted, directed and written.
You do not need to know anything about Star Trek to watch this movie.
A few twists in regards to Spock will make you scratch your head and you may expect more from the battle scenes.
All IMAX screens will give you slightly bigger display, digital projection and better sound...BUT many IMAX theatres like the ones one by my house (aka "LIEMAX") does utilize the super large display you are accustomed to with IMAX. But still worth the extra $2 or $3 nevertheless.