The fit is the most crucial aspect of a cleat purchase.  Football Cleats should be comfortable and snug fitting.  If your cleats are too loose then you will not have good grip on the football field.  "You can't teach speed" right?  Well with a perfect fit, you can increase your speed because of maximum traction.  Football Shoes can be purchased with a hard molded bottom, detachable studs or turf treads.   The harder the surface the less effective the detachable studs are.The conditions that you are playing on make a difference in what kind of spikes.  The Detachable Stud Cleats offer the best traction under normal conditions.