I've tried playing GS and I'm kinda on the fence about it.
It does seem to be quite a good game, though I'm not sure I'll have the time or the ability to immerse myself in it, since there's already FKG.
Not to mention that the Christmas cards will be probably released in a week and I do plan to translate them again.

As for the previous question, yes, I think there's a guaranteed rainbow on the first pull, as I got myself one too.
In my case it wasn't a dupe though.