Not a tad less, but remarkably less. One of them is a heavy, puncture resistant touring tire and the other is a moderately lightweight tire with very little puncture protection. The Marathon Supreme is thicker/tougher than a road racing tire but it is not comparable for a flat resistant heavy touring tire.

My experience has been that the Continental Gatorskin completely eliminated my flats on my road bike. I was running the GP4000S before and they flatted a LOT. Once I got three flats in one ride. One of the tires got cut by an object when it flatted and I replaced both tires with the Gatorskins and have not had a flat since. While I did like the ride of the 4000S, the Gatorskins are not much rougher and this was a good compromise for me. If my bike would accept wider tires I might be more willing to use racing tires on it. Goatheads are commonplace here and the roads are absolute garbage compared to the midwest where I'm from (where potholes are common from the road freezing, so the roads get more maintenance).

On my touring bicycle, I use the Marathon Supreme, although I may change to a lighter/faster tire next time, although the Marathon Supreme is a good balance between speed and puncture resistance. I have had one flat with it where a chunk of glass penetrated the rear tire. I used some shoe goo and installed a new tube and 1200 miles later, no issues.