The track listing tells you that this is not the greatest ever Heavy Metal collection: no Maiden, Sabbath, Dio, Purple, Metallica, Slipknot etc. You do, however, get Uriah Heep, Judas Priest, Thin Lizzy, Alice Cooper and a lot of other bands which cover multiple Metal sub-genres. Some highlights for me are; Mercyful Fate / King Diamond / Venom, early progenitors of Black Metal; the growling doom of Carcass / Bolt Thrower / Sepultura; the power of Trivium / Diamond Head / Helloween; and the bubble-gum metal of Girlschool / Spinal Tap / Steel Panther.
I fail to see the relevance of Styx (AOR crap!) and Mountain (brilliant but not metal) but overall, this is an excellent introduction to many bands who play Heavy Metal, some of which are not well known. At the price, this is defintely worth an investment.