So what do you intend to do? Sell away your US 3DS and import a JPN 3DS?
For me, I initially also bought a US 3DS at launch for 399SGD for the sake of playing One Piece Unlimited Cruise SP and then I realize they have absolutely no intention of bringing that game to the US so I decided to get a JPN set!
And I believe I did the right choice as I am spending much more time on my JPN set than my US set
You should definitely get MH3G! That game is pure awesomeness! Currently clocked over 600 hours on it!