Introduced in 2006, the Marathon Racer is more than 100g lighter than the Marathon Slick thanks to a Kevlar bead and thinner sidewalls.
This puts it in the same weight territory as Vredestein's S.Licks, though it's still heavier than real lightweights like the Conti Gatorskin, Michelin XCR Road or Specialized Fatboy. Apart from the Gatorskin, its rolling performance isn't noticeably worse, however, and its rubber/nylon RaceGuard subtread seemed tougher to pierce. The fact that it's a 40mm section rather than 32mm or similar means it offers that bit more comfort as well. The sidewalls have a Scotchlite strip and a dynamo track, which is good news for nighttime use and helps justify the price difference over the S.Licks. On the whole, it's a good compromise between speed, puncture protection, and a reasonably low weight. If you want something faster, go for the Gatorskin; if you want tougher, the Marathon Plus.
