The controls are tight, the double item blocks cause extreme mayhem, and there are character-specific attacks. Also, some of the courses were amazing. Namely, the rainbow road with no walls, Wario colloseum, and DK Mountain

I just love the DD mechanic itself, it was IMHO a genuine change to the formula that added something to the game without getting rid of anything that made MK good in the first place, not to mention i love that individual teams had their own specials, dont know why the hell that was removed. MK Wii, had good online but overall it felt like a party game on wheels. the challenge was gone, in order to make it more appealing to a wider audience, i get it, not for me. MK 7 is just ok, it felt really rushed, there are a distrubing amount of modes missing. The whole glide/water mecahnic felt tacked on, and was done to much better effect in Sonic all stars 2. Online is ok, i have problems finding a game, but hell its MK

a couple reasons
1) I liked how each character had it's own special
2) the tracks and physics were really well done
3) To this day I still play 16 course grand prix with my friend, it's so much fun. I really wish you could do that with the newer games:/

This post pretty much sums it up.

I would add that the two people on one Kart was a weird gimmick that actually succeeded in lessening the fun factor of the game, and the weapon system broke the game in a worse way than snaking broke Mario Kart DS. Also the track design was the poorest of all Mario Kart games.

If Nintendo hadn't packaged it with the GameCube, no one would have even owned or heard of the game, then the hipsters would consider it the best game of all time.

I haven't yet played Mario Kart 7, so this opinion is subject to change.

Double Dash is the best Mario Kart game for several reasons: its tracks are well-designed and use spacing and height better than any other franchise game; the controls are tight and responsive; and the character-specific weapons and two-player-per-kart mechanic introduces a new level of strategy into the races. It's not a perfect game -- the battle arenas are inferior and smaller racers tend to have an advantage -- but it's fun, it's addictive, and it provides the best local multiplayer in the series.

The Battle Mode was incredible, I really hope they bring it back with MK8. (MK Wii and MK 3DS Battle Mode really suck)

I'm responding to the last batch of post with just this one:
Whether or not a track is good is completely subjective, as there's no set idea as to what makes a track good, since I'm sure we all have different opinions on that. The controls are always solid in all MK games, and DD only has local multiplayer while all future instalments have that (though maybe not as good) aswell as online multiplayer, which has been getting better game after game. The double feature adds more depth/variety, this is true, but also more imbalances aswell, though I don't know if I'd say as much as snaking or bikes. Kart customization, tricks, coins, heck even the gliding/underwater stuff also add some depth/variety, not as much as the double karts, but without imbalancing the game. I don't really think that one feature can make a game overall better than another when it has multiple unique features.
Btw did DD have retro tracks?

Better controls, good use of weapons besides the blue shell, and best stage design.

^But see that's the whole "it's awesome cuz I say so!" thing I was talking about. No real facts or evidence to back up such vague aforementioned claims that can be said about anything.

I never really played Double Dash so i though Mario Kart 64 was the best, There's just greater nostalgia from the tracks. Rainbow road in it's self was just awesome. But from what i played of the Mario Kart 7 demo in the shops, it added some cool stuff like flying, but i can't really judge that game until i buy a 3DS and that game