Mate, Megadeth have some classic tracks and to their credit have never strayed from what they do whether you happen to love or hate what that happens to be.
The same can't be said for Metallica and Jovi (I once loved both but would now rather stick my CD collection up my arse one by one than listen to their painful country twang)
At the very least they're equal. Have you heard him in Suicidal Tendencies? He does all the shit Cliff does AND more but using 5, 6, 7, and 8 string basses. I think Cliff was great but I'm open to saying Robert is better.
No actually I believe he plays session, but Rob Rock did all the writing.