I have tried on all the models of Vibram Five Fingers. The only ones that fit my feet correctly (I have one partially arched foot, one flat foot) are the Sprints. However, I absolutely LOVE them. Whenever I plan on going for long walks, runs, cycling adventures, water sporting, jumping in puddles, acting like a little kid on a playground or climbing anything, I take them.
They've got the friction of the suction cups on an octopus and the flexibility of your feet themselves. My favorite part about them is they are strong enough to not kill your feet on even the most rugged surfaces, but thin enough for me to forget to take them off when I walk in the house.
Only bad thing is I can't wear them to work. But that's perfectly fine. I'm running them ragged as it is.