Often, actually. My main started there. Of course, at the time I didn't have a preference or understand the distinction. Though I will have to say it was nice, as I got to explore the world in a more quiet 'go-at-your-own-pace' kind of way that let me get comfortable with playing an MMO in the first place
Afterward, I liked Galaxy because of the quiet. As a low level character I liked the idea of a more intimate, personal story that eventually opened up to the 'bigger world' of super heroes and mass teaming. It gave me a moment to understand my character's motivations and while not a big 'role-player' in team play, that mattered to me in terms of the rest of that character's development from my own perspective.
When I developed a character with my SG, I went to Atlas because it was convenient, but usually, when I made one just for fun and nobody else was on... I'd go to Galaxy.
Lyc~