Quoted from Eskaybee:

Metallica pros: lyman sheats. exellent integration, artwork, sounds, music. Overall it's a great total package
Metallica Cons: rules can be repetitive in home environment. Lots of bashing of X making it a bit of a grind.
Metallica summary: MET is the overall package whether you buy pro or prem. It would make a perfect first nib but I do question it's longevity in small lineups and/or with good players.
GOT pros: ruleset and design hit on so many levels. Tons of breadth which has all sorts of scoring and strategy opportunities. Lots of big risk/reward jackpots to be had in this game. Good mixture of short and medium ball times. Excellent incorporation of combo and playfield muktipliers. Rory McCann (the hound) has killer call outs.
GOT cons: not necessarily a con, but its not a story based game, this is a players game. Missing critical sound queues for big jackpots (HotK hurry up SJP and WHC super jp to be more precise). Pro is one ugly machine (must buy an alt translite. Code needs bugs polish and fixes. This pin is not everyone's cup of tea - make sure you understand it before a purchase.
GOT summary: if you get past the artwork and learn the multiplier rules, the game is one of sterns best. I prefer the pro over the prem. Tough choice for a first nib though as it doesn't have that total package that metallica does - unless you're a player looking for strategy and adrenalin over anything else.
GB Pros: I don't like the pro version and prefer the LE. Magna slings and LE right ramp are awesome. Dmd, sounds, and music are some of the best. Except who brought the dog. Art package is amazing
GB cons: tough brutal game. Scoring seems awkwaRd and imbalanced but could be me. Playfield quality issues.
GB summary: excellent game but verdict is still out on longevity in home use