Ace: Ace was a breath of fresh air, especially considering a lot of post Gaim main riders (Except for Drive, and Build) we've been kinda generic ass goody goods who's morale is never changed throughout their shows.

Ace is not only cool, I love a lot of banter he has with some of the characters, but I also he offers a lot of unique perspective on things for them as well. And while some aspects about him you could argue make him a bit of a Gary Stu, I chalk it up to him having experiences what with him constantly being reincarnated every time.

Which is more I can say for certain other characters who I argue are bigger Gary-Stus than him
Cough Takeru Tenkuji.