I got them (flip ups) with my Nikon Monarchs and I personally don't like them. If they opened like 100 deg it would be one thing but opening 180 deg I find that they get in the way. I prefer the scope caps I got with my Vortex scopes which are just held on with bungee cord. You get a reduced quality image with them on, but not no-image. So if I am out in the snow or rain, I might get off an opportunistic shot which I would not with the flip up caps.
I appreciate the feed back. I just thought it odd that all the hunting shows I see never show caps. Thinking about it, the scope manufacturers probably don't want their products covered.
I also kept my range dope inside the flip cap. With the Nikon 3-9 with the BDC I'll probably do the same thing.