He ran the Pikes Peak marathon in 3:27min. The Pikes Peak Marathon course starts here at 6,300 feet, before climbing more than 7,700 feet to Pikes Peak’s summit at 14,115 feet. It then returns to the start. It is on trails (not great ones). It has switchbacks. Kipchoge's course had a total of 18m of elevation gain, and a net of around 5m...it was on roads with corners designed to not slow him down. Kilian's runs aren't just about speed or optimization they are also about significant skill. It's the tortoise and the hare...I don't know Kilian's outright best road marathon time, but I'll bet it would be extremely competitive but not world class. Eliad would win a road 50k (31mi) I'd bet, but I would put my money on Kilian for a head to head trail marathon or a moutnain race, or a 50miler.

As a point of comparison Jim Walmsley holds the outright record at the Western States 100, his pace was 8:30min/mi. He also holds the 50 mile world record at 4:50:08 (5:48min/mile). He ran the US olympic marathon trials this year...he finished 22nd with a 2:15:05 (5:10min/mi pace).

Funny enough, 2:15 seems to be a common marathon time for elite ultra and mountain runners [0]. Those last 15mins are HARD, the last 3min are beyond my comprehension as a person who prefers ultras and mountain races over the road marathon scene. But so is a marathon at altitude with 7,700 ft of climbing. So is a 50 miler at nearly marathon pace. Give them a road marathon, Eliad will crush the other two. A mountain course with tons of climbing and scrambles and choss, I'll pick Kilian. A reasonable but very long course (>50k), I'm going to pick Jim. They are just hard in very different ways. It's like comparing a rally car to formula one car to a le mans car...different optimizations.

[0] https://www.fastrunning.com/training/marathon-training/kilia...