I bought this recently and I have to say it was a disappointment. I'm a Sim fan but this isn't anything like the PC games.
Firstly, you design one sim, not a family. Then you're sim is rapidly put in charge of a hotel, you can't redesign it, just add ready made rooms. Sure, you can buy furniture but a limited supply that does little to the gameplay.
The game runs on real time and you often you have to build something which takes eight hours (I'm not exagerating) leaving you nothing to do in the meantime. You have to turn your DS off for eight hours and play again later.
There are some interesting events, like aliens invading but honestly I'd say you should save your money and either buy the PC version or look for another DS game.