As a band they're pretty horrible. Not one good album from start to finish in their entire career, and their debut is one of the worst rock albums I have ever heard, no exaggeration. The entirety of their good selections can be found on their 1998 Greatest Hits album, and even that has a few turds in the punch bowl.
That said... most of those songs on that compilation are some of the best songs rock music has ever had. It's not enough to redeem the rest of their awful catalog, but I'll never say a bad thing about songs like Kickstart My Heart, Too Young To Fall In Love, Girls Girls Girls etc. Shout At The Devil sucks, but Motley Crue is strange in that they have lots of lows, but their highs are almost unmatched by any other hard rock group.