Well, the fact is...none of the armor is worth purchasing. UNLESS you're going for 100% Armory completion, and then its all worth it.
I mean, right now I have the StormCloud thing. I'll buy the Grunt Birthday party and the Hearts...but I'll still only use the Stormcloud. The only reason for purchasing these things is for your own personal feel and to gain that 100% armory completion.
No real Achievements or even Commendations for it that I know of.
the higher up you go the more items you can unlock. You can even get a gold visor. It's up to the person to figure out how they want to look. I'd google it and see what all there is and see if you want to keep saving or not.