Now i might get some flak for saying this, but in my opinion the design on 5 fingers looks like it came out of my 6th grade science fair.  Any shoe that forces you to place each individual toe in a sleeve is not for me.  Innov-8 always makes light shoes but the F series spoils me to no end.  The feel great and weigh next to nothing, and they look nice.  I love these shoes and will beat anyone in an obstacle race if they say other wise.