I considered both systems and decided on RB.

I decided on RB because parts and modules are widely (much more so than GS-1) available. Rotating back feature was attractive but not the deal breaker. I wanted a lighter system but when I have to carry a few lens and other "stuff" anyway, it wasn't going to make that much difference. Weight was an issue but going to something like Mamiya 7 was prohibitive (money wise). So balancing the benefit and issues, I went on RB.

If you like the GS-1, go for it. There is never going to be "the best" choice that everyone will agree on.