I own and/or operate pros, premiums, and LEs of Stern Games. IMHO, stick with the PRO and save money on Iron Maiden.
The extra $$ are not worth it on Maiden (i.e. game play is not significantly enhanced with the premium). In other games, you may be losing an extra playfield (upper - Black Knight, Game of Thrones, etc. or lower - AC/DC, Munsters, etc.) or significant features. For me this is not the case with Maiden. Is it nice to play a premium or LE? Of course. Is it worth $1,500 to $3,000 more? I don't think so!
As a final note, the Pro is still an enjoyable game, however, a little on the easy side (long game play) for my tastes. I would go with Jurassic Park!