The Noble has the advantage of using acrylic faceplaces so you can't see the silicone artifacts so well, plus you get artwork and all that. Even ignoring that the quality is still excellent - not as clear as acrylic, obviously, but pretty transparent and with no visible bubbles or other imperfections. Finish is fairly smooth, not grooved or rough. The Custom Art is much the same except no acrylic faceplates. The clear parts of my Music One are actually a little "clearer" than the Noble but it's not a big difference.
The SE 3-way Reference has some roughness to the finish and feels a little more "rubbery" at first. This goes away over time. No bubbles that I can see but it's a dark shell. The Sensaphonics have some bubbles, etc, and aren't as transparent as the Music One or Noble.