I have a pair and love them. I wear them for hiking, running, river floating, cliff jumping, basically summer stuff. You definitely can't run by heel-striking or else you get real sore heels. If you want to know about forefoot striking read this.
http://www.barefootrunning.fas.harvard.edu/4BiomechanicsofFootStrike.html
Forefoot striking actually strengthens lower leg muscles/arch etc.
I love my five fingers for a bunch of reasons. First off, if you get them wet they dry quickly and comfortably, makes them awesome for river/lake stuff. The sole is also made of super grippy material so I use them for some recreational climbing.
Bottom line, try some before you bash em. They feel natural, like how you felt running around barefoot as a kid. Except you don't need to build up calluses, and don't cut ur feet the fuck up. Don't get blisters or sore arch. fun to run in.