If you spent countless hours playing the original N64 game, you should play it in 3D then.
I think what I like the most about Star Fox 64 3D is the fact that it feels exactly as it felt back in the days, when I – a child back then – would immerse in the action and play countless hours. But this time, even with the small screen of the 3DS, the graphics are so much better that it looks like a whole new game. It also may be a little difficult at first with the 3D effect on, but you're sure to handle it in no time.
If you love the series (if you ever played Star Fox, you probably love it) and you have a 3DS, don't let this game go unnoticed.