Hey Nito,
It works very differently from Sim City. There are over 80 different maps. The maps are massive basically the size of a region in Sim City if not larger. Each map has its own benefits and specialties such as water production, oil reserves, holiday destinations and agriculture areas.
It's far superior to Sim City in every single way.
Here's a video review to get you more interesting
Cities XL 2011 - First 10 Minutes Gameplay (PC)
Cities XL 2012 Review - AddMeGamers
Cities XL 2011, 2012 and Platinum are essentially the same game but each year more content arrives.
I'd like to see more people here give it a try over Sim City just because of the awesomeness you can build and share. This game has so many mods so you'll never find yourself bored of the same content.