I liked the older ones with a tube long enough to get past the diopter. The screwy ones are too short on a couple of mine. And the older ocular covers with the red BC style pushbutton were a whole lot harder to open accidently against a coat or pack(while slung), than the long-stemmed new style....
I prefer the old style with the red button - the new ones really stick out there a long ways, making it easy to open accidently, but also easy to snag on my tender flesh.
