I know that shoe fit is a pretty individual thing, so here is my experience. I am a male 150 lbs / 6'. I run about 30 miles per week year-round (gotta love the weather in San Diego). I am currently training for my fifth full marathon. I finished my last full at 3:38. I have bought many running shoes, but I think the Cumulus has got the perfect amount of cushion for long distance running. The Nimbus just feels too "gummy" and not springy enough. I definitely want some of that elastic conservation of energy so I don't feel like I am spending a lot of energy in every step. The Nimbus is very good on your joints though, but I don't have a problem with that. I do start to feel some knee impact in ASCIS shoes with less gel than the Cumulus. Also, even though "they" say you're supposed to have more springy shoes for the race day, I like my cartilage tissue too much so I have always run my marathons with the Cumulus. One very important thing though: I normally wear shoes size 10-10.5. For running long distances, I buy these at 11.5 - otherwise, I have injured my toes before. I hope this helps.