There are times that I'd swear a female Hendrickson spinner made all the difference, and others when it didn't matter. I think it depends on the speed of the flow and number and type on naturals on the water. When I think about it, the egg sack at times mattered some on the slow flat stuff.
All in all, the fly you have the most confidence in (within reason, of course) will keep you focused and transmit that lucky juju down your fly line to the fly.
Joe