It's up to your preference, really. I don't use either for messaging, for instance, as I prefer Textra, but some people like how better integrated Samsung's apps are with its OS, especially if you still use their stock launcher. Some like Google's aesthetics and tighter Google Services integration.
As for the bubble color, yup, you can change that in the messaging app's settings. There are a few templates to choose from. Not as customizable as some 3rd party apps, though.