SnG, I like SnG because you are aiming for a target and that makes it easier for me to play well. In ring Games there is no aim or target, you can set these yourself though.
In Ring Games You also can suffer massive fluctuations in your chip stack which can seriously effect your bankroll.
In SnG Tournaments Games you pay a fixed feee, and it doesnt matter how much your chip stack fluctuates its not going to harm your bankroll in any further way.
SnG games are also good because at the beginning of the game no-one has a chip advantage over you, so the play is alot fairer.
In the end you need to play a bit of both and make your mind up what you like playing.

No one can tell you, you have to make up your own mind through your own experiences, your strengths and your weaknesses.