Let's put it straight - heavier than Sabbath it is not, neither it is as good as Deep Purple. Yes, the short-lived British hard-rock outfit was patronised by and produced (overproduced to a certain point) by Ian Gillan, but a musician of his caliber certainly could afford a pet project*. The connection with Gillan is, perhaps, the best thing about the band (and abused for promotion purposes). On many occasions the words which Gillan said about "Jerusalem" are quoted, but without refrerring to the source - forgive me, but I couldn't find it, and (although I didn't touch for a long time) the project is not mentioned in his authobiography (Ian Gillan: The Autobiography of Deep Purple's Lead Singer). That was a nice effort - promising, the act was still in search of their music, and vocals are rather unsteady. Loud and noisy? Yes, they were - what so special about it? So was Blue Cheer. Scottish IRON CLAW - IRON CLAW, the first true Sabbath tribute band, were much heavier, while Zior was seriously messing around with occult and magic. Definitely not a must - unless you are a completist, or seriously addicted to hard'n heavy of the 70s, but if it's your first venture into these years, I would advise to listen first to still underrated Rare Bird, pure and menacing hystery of Gestalt (Dig) and eponymous The Entrance To Hell... Even forgotten Zakarrias - who had a mifortune to be signed by the same label - is far superior, without mentioning fiery concotion of high octane and pure adrenaline of Clear Blue Sky.
Otherwise - yes, once there was a band which went on crusade to Jerusalem, but got stuck somewhere in Calais..
Yes, the CD is good, and covers almost completely the heritage of "Jerusalem" - 14 tracks altogether (9 from original LP + one track from the single + 4 previously unreleased bonus tracks).
A cornerstone of future NWOBM? Gross exaggeration
The original members of the band were: Lynden Williams (vocals), Bob Cooke and Bill Hinde (guitars), Paul Dean (bass), Ray Sparrow (bass). After releasing debut LP, "Jerusalem" managed to squeeze out another 7" maxi single (featuring "Kamikaze Moth").
* Ken Hensley of Uriah Heep was also involved with few side-projects, but more sucessfully - Weed...!, Orgasm. Gillan, by the way, never considered himself a great producer