Hi Steve
They are both superb phones but if you read reviews on both you will come to the conclusion that the edge looks very cool but it isn't a feature you would use so if I was buying either it would be the S6, if she can wait a while they have just launched the S6 Active in the States and it will be released here at some stage, now some people thinks it's ugly but to me I think it looks fab and the main reason why that is the one I would buy is it has a much bigger battery than the other two phones it is a 3500 so the battery life will be superb also it is waterproof and dustproof as well and for me good battery life is a must as these screens really drain power.