I installed the blind on the inside of a window frame. 

Pros It fit true to size. I ordered the slate colour and it is a nice light grey - exactly what I wanted. It took me some time to get used to the spring mechanism, but now I like it much better than the folding blinds I had before. 

Cons If using this inside a window frame, it will still leak some light out the sides. However this is to be expected since the gaps are necessary to fit the mounting brackets.

I would buy this again.