AC:NL FTW You are fricking mayor. it's bawss.

I can tell you from personal experience:
MK7: Racing is really fun. You unlock kart parts by getting coins from each race. (10 total per race) You can race each track as many times as you want to get more coins.

Each part requires you to get a certain number of coins to unlock. First hundreds for the first few parts, then thousands for the later parts. You don't pay coins to buy parts, you accumulate them to reach milestones.
You also unlock parts for beating a Grand Prix, beating someone you streetpass etc ..... but you don't have to do that if you don't want to or can't. You can just gain coins and you'll eventually get them all.

to be continued ......

AC:NL: Being mayor is really fun. You can set up projects like lamp posts, benches and water fountains to make your town look awesome. In a sense, the whole town is your "house" to decorate. You can use patterns on anything, even furniture.

You can go to an island to play minigames with people on your friend list when you have them over. Special furniture can even be bought there.
A new feature is special rocks (1 per day) that when you hit it, yields special ore that can be used for special furniture.
There's special fruit, K.K. songs to turn into music boxes (I kid you not), spotpass DLC (all free) literally too much to mention here.

to be continued ......

Ultimately, it depends on what kind of gamer you are:

If you like fast pace racing, periodic unlocks of parts, beating other people's times and online racing for leaderboard dominance (as well as online battle mode), then MK7 is for you. You may never get tired of it.

But if like taking your time, collecting everything possible, customizing more stuff than ever and hanging out with people on your friend list, then AC:NL is exactly what you want.

to be continued in final part ......

Personal thoughts section 1:

I'm not very good at MK. I couldn't get triple stars in MKDS nor MK Wii. (still can't)
That said, MK7 was easier by comparison because I was able to get triple stars with some effort. Because of that, all that was left was to race and battle and race for the 10 coins per course. It gets monotonous after a while.

I'm not very competitive, so I guess the monotony gets me the hardest. Records don't matter to me much so all I have left are the coins for parts.

Don't get me wrong, the game is fun and it does a good job of keeping you interested. I just prefer cooperative games that's all.

last part next I promise -_-;

ACNL, it's awsome! Yeah Mk7 is fun, but you can visit your friends towns and do allot of different things. I really enjoy the game. I have Mk7, but don't play it much anymore. I have been playing AC since the day I bought it.
^-^

AC:NL is really slow paced. Once you do all you want in a day you'll run out of stuff to do and can get board pretty fast. On the other hand, if you play non-stop each day you may get tired of doing the same routine. Then you may not want to play anymore, even if you still have plenty to do.
It's up to you if you prefer playing by yourself, but great replay value can be had from inviting others to your town and the island. Show off your home, town and clothes (buy more pants and shoes for the first time ever)
Even though you're the mayor, you can't kick out villagers ypu don't like. WHAAAT?

Hopefully I helped you make an informed decision. Sorry that all this took so long. -_-;

The End

Mk7 is fun so get that 1 x3

mk7?
what's your fc?
mine in my gallery :D

I love them both, but ultimately, I think I like AC: NL better :)