Sorry for old thread revival, but I happened to have all three brands in my garage so thought I would add a picture.
Fine Lines on left, Classic Tube in middle, Right Stuff on right. Two pics are under slightly different light sources.
I have to say, I have really enjoyed working with Fine Lines. Incredibly responsive and helpful. Classic Tube was nice the one time I called them, but don't have as much experience with them. I'm guessing the Classic Tube will be closest to original?
John