I am not much of an expert as I run less than most of the other gals on here, but I did buy trail-running shoes last year (Vasque Blur) and love them. The trails I run are very rooty, so I was looking for a bit more stability than a super lightweight road-running shoe. I don't notice them being hot, but I did not get ones with a Gore-tex liner. I must admit that one of my motivations for getting them was keeping my road-running shoes nice and clean, since the trail I run on can get pretty muddy, so my trail shoes don't stay pristine.