Its almost exactly as if you removed first gear and added another gear on the top.  Shifting into sixth gear comfortably with no stuttering occurs at about 55mph and 3500 rpms.  Fifth gear is around 43mph.  I think of it like a five-speed with an overdrive.  Top end is supposed to be around 115mph.  I've had it up to 102 with plenty of throttle left.  The loss of the bottom 'gear' doesn't matter much on the street or well defined trails and open fields.  Still has blistering acceleration.  But dirt performance goes out the window obviously.  The purist dirt guys are going with 14t sprockets.  But since I'm 75% street 25% easy trails, it works out well for me.  Remarkably well I might add.  I'm completely convinced this is the greatest bike of all time, and I've owned a bunch of 'em.