On long distace open roads, no doubt fixed is tougher. How much is the question. I think 1: 1.5 is too high unless you are talking mountains.
My guess would be 1.2 - 1.3 for rolling to moderate hilly terrain.
Break vs. no break is another important factor. No brakes on long descents can really kick your ass and wear you down.

I would say those are the two biggest factors, terrain and brakes.