Narrow heel cup, which worked fine for my feet, and a quick break-in time. True to size for me. Great cushioning, my feet felt fine after a 5 day, 50 mile backpacking trip. Very lightweight for how tough the soles are an the waterproof package. However: the pull tabs are not well designed (i.e. you can't really pull on them ...). Small rocks/dirt easily get in the by your heel. The material on the toe cap was also peeling off after minimal use, so I wonder about the durability. Water proof only in toe-deep water - don't expect the uppers to keep your feet particularly dry.