Summary: It used to be, I was not able to see the inside of my view finder easily, I could never get the diopter to focus. I've always been farsighted, so I chalked it up to my optical prescription. The easy to follow directions instructed me on how to remove the viewfinder from the camera and attach the viewfinder to the extender, and install the extender back onto the camera. I was finally able to focus clearly inside of my viewfinder.
Summary: I have a lot of problems with nose bruising after a long shoot. Also with intense shooting, fatigue keeps my face back so I can't see the entire image while shooting at times. Got this for the sole purpose of getting my face away from the camera. Does that job very well with a few hitches. First, I'm not used to the eye piece being so far away from the camera, so I've actually rammed it into my eye painfully. Getting used to it, so that should go away.
Summary: I wear glasses, and normally have to remove them to really see what is going on in the viewfinder. Finally, I can leave my glasses on and tell what I'm doing. That's a first for me. The image is slightly small, but certainly better than having to fight the glasses all the time. I never take them off now.
Summary: I really like having the eyepiece extender on my camera. It makes you less likely to put smears on the LCD on the back of the body. It is easy to install. The only drawback I have is that the eyecups don't always stay on it. This may be a problem with the eyecup or this product. Regardless, you'll have to keep an eye out for jumping eyecups.
Pros: Easy To Use, Improves Product Function, Lightweight