This is a wonderful add-on. Finally I don't have to stand these ugly non SI units. It would be nice to also have the option to remove the Imperial altogether and provide a tool-tip if something was converted.
The basic add-on already deserves a 5/5, however. Thank you very much!

One thing which is funny is that the description says "Convenient for amazon shopping, cooking, etc." .... Tablespoons do not get converted yet, but then again which idiot would measure in spoons and then say it is an exact thing in the first place.... (ah yes, the internet)

This addon was exactly what I was looking for! I had gotten completely fed up with trying to parse outdoor gear specs back and forth between metric and imperial. This makes it effortless.

I hate imperial units so much! Thank you! You are my saviour!

I have been looking for something like this for a while (I sorely miss the old "Converter" extension!). I have just installed it and the first impression is very positive! Thank you!

[EDIT] first impression confirmed - works really fine for me.

If you are looking for ideas, to further develop this project - In 2015 the developer of the Converter extension ended development and released the code as Open Source - you can find it here https://github.com/Gutza/Converter