I've got Tenebraex, Aadmount, and Defenders on my scopes. Not sure which one I like the best. I didn't like the Aadmounts at first - couldn't get them to close, but once they broke in they're great. I like the push-button opener for the eyepiece. But I can't say I have a real favorite. Tenebraex and Aadmount seem a little more "refined" than the Defenders. You'll do fine with any of them as long as you get the right fit, and you don't get Butler Creek. (That's a real shame, because they used to be good but they are worthless now).