From April 19th, 2014 to December 2nd, 2020, 100% user give 5-star rating. for Rot13 Decoder chrome extension.
It does exactly what it says it will. Lightweight and very handy.
My only reservation is that the right click option brings up an alert so i can't copy the plain text that way, i'm sure that in a future revision this will be fixed >.> apart from that lightweight and very useful :D