First, welcome to the forum, and the war, daones. Second, thank you for serving our country, you have my respect and sincerest gratitude.

I'm glad everything worked out for you with Steam. Though I have no personal knowledge/experience with that particular version (Steam), I read alot of horror stories involving many different games DLed from them. Then again, I've read just as many happy experiences about Steam.
I would heartily recommend any of the supermods, the preference of which is simply a matter of taste. TMO, RFB, are both equallly (in their own right) truly, super, mods.
Still, though some have had absolutely no difficulty transitioning to the supermods, you may want to play the Stock version for a while and acclimate yourself with the game's dynamics. It could, potentially, save you some degree of frustration later on. The game has a bit of a learning curve associated with it. Just be prepared for some minor withdrawal symptoms (depression, DTs, PTSD, etc.) associated with long absences from the game. Oh yeah, mutiny from the home crew (first mate, etc.) has also been reported by the forum debriefing team.
Anyway, welcome aboard!