I voted Met pro by a hair over Maiden pro but could go either way I just got Maiden so it's in the honeymoon period.
Maiden has more shots (upper loops) but not a lot of toys.
I have played BSD but never got the strong desire to buy it.
I love both Metallica and Maiden, art, music, flow, rules they both are the complete package. Maiden for the larger display but Metallica is a SAM game. I can not forgive Stern for placing the on/off switch on the head.