MTTs differ most from NL ring in that the blinds and antes are always increasing. Learning to effectively manage stacks of all sizes is an important skill in tournaments, much moreso than in NL ring where you can always go back to your bankroll for more chips. Final table play is also a very important skill that differs a great deal from NL ring, so I'd say learning the aspects of short-handed play and how to adjust your strategy accordingly are another important aspect of playing in tournaments. Sit n' Go STTs are a good way to hone those skills since they most closely resemble final table play. I actually think the turbos are closer to emulating FTs since the blinds rise fast enough that they're usually a significant portion of your stack by the time you reach the money.

I'm guessing you may already know these things but figured I'd point them out just in case. You never know....