Iron Man is my favorite from your list by far.
LOTR is a good game, but long and the easiest of the 5 you listed.
Not a Jersey Jack pin fan.
I owned an Avengers, my only NIB purchased pinball.
I loved it, but it's construction is weak (too much plastic) and Stern refused to update the code when it needed it badly, so I sold. Still, fun game that can easily be made easier or tougher.
Good luck-