Think of it as the non-crappy version of SimCity '13
Then I started hearing good things about New Leaf and took a chance and I will say, this has to be the best installment in the series yet.
When you first start up you'll notice some major changes. While riding on the train with Rover the Cat (who notes he's been on the train since 2002) you actually get to pick your city from different maps. Then upon arriving a mix up in communication has you as the mayor of your town and Isabella, your personal assistant gets you set up in the Mayor's office. Then Tom Nook who has moved up from simple landlord/store clerk to Realtor has you walk around and decide where you want to put your house. So now I have beach front property within walking distance of work. You'll notice other returning characters have changed up things. K.K. Slider is now a DJ in a night club, Tom's sons Timmy and Tommy run the store, the Able Sisters along with Labelle now combined their shops together and Kap'n still gives island tours.
Another big change is there is a lot more customization. Your avatar is taller now meaning you can now buy pants. You can also customize the exterior of your house as you're paying on it buy chosing items from Tom's home store. I also like that more recent entries will allow that when you give a piece of furniture to another resident, they display it in their house.
While the usual tasks of paying off your loan, collecting bugs, fossils, fish and paintings for the museum and helping neighbors is still in tact, your role as mayor adds a new level of depth. You now have to work to please the residents as well as you can set up public works projects and ordinances. In this installment, the longer you play the more the town grows. A couple weeks in and a garden store opens, another week and you can visit the island which for me not having a GBA meant I missed out on it on the GC version.
Speaking of the island, while it's small, it has a lot to do namely it has an abundance of the rare fish and beetles if you want a full museum as well as make a lot of money. It also has various mini games you can play with Tortimer and for the first time in the series, you can buy a wet suit and swim around the island. Many times I just like going there to listen to Kap'n sing during the boat ride.
Finally it has an online element where you can open up your town to visitors or visit other people's villages as well as a bizarre dream sequence which I haven't had a chance to experience yet. Every time I'm online, no one else seems to be around.
I would definitely reccoment Animal Crossing: New Leaf. Especially if you had started to lose interest in the series. This one expands on the original gameplay while keeping all the original elements in tact.