It's weird how shin and Go feel tonally different towards the end, at least compared to how G and the original was due to the cosmic horror and the nature of Shin getter and getter energy becoming less heroic looking in terms of its behaviour and skills (Go and the stoner sunshine nuking + the final fights or Shin with the Getter G and the doctor going crazy).
I liked the Alaska arc the most with Go though, though the second arc still sticks with me when I think about that manga.
Was nice seeing other mecha pilots. Only gripes were the lack of getter for a while. Though the titled robot got cucked out of relevancy pretty hard in general.