Yes, the power-ring on the E1 is large. The standard FFII does not have a power-ring; instead the entire eyepiece turns, so they can be mounted in lower rings.
Right now I only have one E1, which is on my .17 Hornet, used mostly for ground squirrel and prairie dog shooting, where dialing is more precise than using a ballistic reticle. I have never been able to see any difference in optical quality between the E1 and the standard models, but some people claim they can.
I am not crazy about the E1 BP reticle, much preferring the standard model.
