It's an absolutely fantastic game, but if you've never played it before, be prepared for a bit of a learning curve initially. Nothing to great, and there is a sort-of tutorial that pops up context-sensitive tips if you need them initially. Once you get the hang of it though, I don't think there's many games beyond MMOs that can compare for sheer longevity, replayability and addictiveness.
I've put over 150 hours into FM09, 180 in FM10 and around 130 so far on FM11 - time will just disappear once you get the hang of the game. There are so many different ways to play, too. As you say you've not played before, I'd start as either your favourite team, or a powerful team like Barcelona. This'll let you learn the ropes while you have a good side which should ensure unless you make some drastically bad decisions, nothing will go too wrong. Then once you're familiar with the game and looking for more of a challenge, you could take control of a team in one of the lower divisions and try to lead them to the top.
That's without mentioning the custom content available from the official forums - people have created their own leagues such as a world superleague, which could provide even more play time. And then there's the editor, where you could create a team of you and your friends and see how you progress, although this takes a long time because of all the stat editing required.
In short, it's a fantastic game if you have any interest whatsoever in football/soccer. If you're willing to spend a bit of time learning the game, which it does a good job of teaching you, don't hesitate to pick it up - although saying that, it may well go on sale on Steam soon during the Summer sale.