I added one on the r/s of my 67, I like the way it makes the looks balanced out.

The key for actual usefulness is to make sure of the correct mounting location.
It's farther back than the l/s mirror by several inches.
I asked on here where it should be located and all the responses said "even with the drivers side" which was wrong.
I drilled the holes based on that, the mirror is useable but slightly blocked by the A-pillar.
To make the mirror completely useable it has to be mounted in the correct location.