For disclosure I have an anthem 29er Alu which I raced XCO and XCM for two years.
It wasn’t the lightest, and the rear end became a congealed mess on clay like muddy races. But in all other aspects it was excellent. A good climber and very efficient capable suspension now enhance by a 129mm Reba.
I always found Scotts to be expensive for the sum of their parts, and not necessarily light. People I’ve know with cubes either snap them or claim them to be uncomfortable. I’ve raced a guy with the canyon Lux – looks magnificent for he money, as does the Orbea. Rollingdonut from here had a Trek top fuel which looks fast standing still and just a sorted option.
I’m not a hardtail man but I took a risk on a Vitus Rapide Carbon HT. Dont discount that frame which is of Chinese origin and available to many, its surprisingly comfortable, light and fast. I rode mine on the Torque 6hr and it was never an issue, and will be my Scott MTB Marathon bike of choice. I’m using the Anthem for 12hrs this year for the extra comfort.
In my view, 6hrs or less you should get a carbon HT. I’d go carbon Anthem 100mm, or Top Fuel as my Marathon bike though for the platform support both bikes bring – the Anthem through design the Fuel through the shock.