>>3998913
I personally prefer the 3DS games, but if you're planning on playing the DS ones at all you probably should play them first.
Part of the charm of the 3DS games is that they take place in the future as a next generation kind of thing where you see older versions of the original cast pop up from time to time, there's also spoilers if you care about the story.
Either way the main campaigns of the games can be beaten pretty quickly, though every game has autistic levels of post game content that most people probably aren't gonna actually do.