Basically I have to differ with this review between the reasons for the acquisition (point A) and my experience after the purchase (point B).
A - reasons for the acquisition of FDA-EV1S:
1. in bright sunlight, it is difficult to correctly adjust only display the image here a viewfinder is indispensable.
2. The viewfinder is angle adjustable, so I can see from above by the camera, a clear benefit to the built-in viewfinder of NEX. 7
3. Only in the viewfinder I have the opportunity to see all the settings in an overview (without motive / picture). This makes the composition immensely.
4. Automatic switching between the viewfinder and display by eye contact. Optionally manual switching keystroke.
The only disadvantage, through the viewfinder of the shoe for the flash is blocked. I think that's not so much bad, because if it is too light and the viewfinder is important, usually need no flash. If it is too dark and the flash is important, I need no viewfinder. Only the demountable is a course not spared.
B - My experiences with the viewfinder after purchase:
The viewfinder is very light (26g), thus increasing the weight of the NEX or the carrying case only minimal. The build quality is super.
The most important is of course the picture, and that's a dream. Razor sharp, very detailed and realistic displayed. My expectations were exceeded. I have tried many EVF, but the Sony beats all.
For me as an eyeglass wearers very important is the continuous diopter adjustment.
Should If you develop in Live View mode noise must be changed to the following:
Setting - Live View Display - all settings
The result is a noise-free picture!
Conclusion: an expensive seeker who his money's worth though!