I love my monster premium. my first NIB pin
while I wouldn't say that I'm a huge metallica fan (never seen them in concert, I do like a lot of their music and borg and lyman blew the roof off of the factory with this one. great rule set, nice flow and fantastic layout and toys. I love the fact that apparently metallica (the band) was adamant about the machine having metal ramps (all models) [at least that I was I have been told]
both version of the game play well and unlike many of today's titles from stern, the pro doesn't feel like a stripped down version of the premium/LE, however the added features on the premium/LE are really nice and lend themselves as really nice upgrades (think of it more as leather seats vs. cloth in a car)
the spinners are integrated into game play and as was mentioned before, tying them to the tom drum sample (especially with a sub woofer) is just one more detail that makes you smile
personally, I don't think that the hammer blocks or obscures any of the shots to sparky (while it may do so for some of the shorter players out there, it's definitely no where near as obtrusive as that huge plastic abomination that is wolverine
yes, the rising/lowering cross tombstone doesn't affect game play, but again it's a nice touch and something that typically wows guests when they see it for the first time. plus, it operates so smoothly and ties in perfectly with the DMD animation
finally, I think the articulated snake jaw is just another really nice touch that does a much better job of letting you know when a shot is available vs. the LED on the pro. people have stated that they don't like the hammer because it "slows down play", but on the premium/LE, if the snake jaw is closed, your ball bounces off and opens it, allowing game play to continue seamlessly vs. the ball getting captured and then spit back out two seconds later on a pro
remember, no one's opinion is more important than your own. don't take anyone's word for it. take the time to play the different models that are available for a specific machine and purchase the one that you like the best