I find the best litmus test for bands like these is this:
What sounds cooler when a pro wrestler comes out to it?
G n'R?
Not really. I'm sure some tosser working the county fair circuit has come out "Welcome to the jungle" or something, but there's no real way for the crowd to get hyped up behind that. No, no, no.
VanHalen?
With Hagar, no way. They'd be coming out to some power ballad. Maybe "Poundcake", but even then, it just sounds too gay to come out to. Maybe "dreams" or "Best of both worlds" could play when you win, but that's about it. "Jaime's crying" or "Eruption" maybe good ones for coming out to, but there's not really a good moment to shake your mullet and lean back into the crowd in those songs.
Metallica?
The Sandman entered to 'Enter sandman' for years, and although it might be one of the more hated Metallica albums, people dug it, especially frat boys. Metallica's old stuff, while universally beloved by everyone who universally agrees that they suck now, is a little too choppy to walk to the ring to, unless the person has tourets, whcih is always possible in wrestling.
Verdict: Metallica
(although I prefer Roth era Van Halen)
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Peeing sitting down is the gift you give yourself.