Seeking opinions, thoughts, experiences, etc on the Relief 66 fountain pen.

I may have an opportunity to get one but wanted to hear from anyone/everyone who has/had one. I have a Relief 2-L, a Relief 12, a BHR Dollar pen, and ten or so Esterbrook Js. How would a 66 fit in? How will it compare with those I already have? Is it different enough from the Dollar pen to make it worth acquiring? Any other thoughts? TIA