I played with all of them, and didn't like R45 all that much. Must be me; it was way too bouncy in areas of the game where I really don't need that, and it felt limited in terms of speed/spin pressure.
G1 and GA8 are not alike. GA8 at 48º is nothing special, and I don't think I could distinguish it from Xiom Vega X, Rasant Grip or Rasanter R48. All of these have playing characteristics that rapidly change; after of few weeks playing they're different rubbers entirely. Once the ball starts slipping off they're unusable (to me). This happens after two, three months of playing. GA8 at 50º is excellent, as long as it lasts; but that too expires rapidly. From my limited experience with Genius, Aurus and the like I think they're in this category "plays fine for a week or two" as well.
G1 lasts and stays predictable, and does not bottom out easily.