Guess I'll have to wait until I can see it in person, but from the pictures (and judging from the way my GG slim looks), I like the older buttons better (all brass). I think my favorite is the original flat button that has the locking nut with the groves in straight lateral lines.
Tim, if you pick up a new button and end up really liking it and having no use for the older one, shoot me a PM. I was planning on purchasing an older button after I received my GGTS and sized up the new one. I wouldn't mind saving a couple bucks if possible.