Assassin's Creed II is a good game, ignoring the rather paranoid move of a permanent internet connection requirement
Taking about gameplay, it is recommended to use a controller, because the keyboard is very awkward to use. Once you have your controller, the gameplay is innovative, and very fun. It is quite satisfying to successfully perform a counter with the hidden blades or climbing a massive building, and all you only dream of ever being capable of doing. I applaud Ubisoft on their work, at least they don't rip people off with milked franchises.
The other great thing about the game is the great graphics and a soundtrack that fits the everchanging situation in the game, whether it be in combat, or during a morning run in Florence, or even in the mountains, where they have their own distinctive music and culture.
Being a sandbox style game, there are many collectables, and all of these actually have some affect and meaning, some even essential to the main storyline. Since the game goes through 28 years, things do change, places change, people change... well, maybe not people so much, but anyways it still makes this game very unique, and I think that's whats important. However, there is one annoying this about this game, and that's the permanent internet connection requirement. It's a real curse by Ubisoft, making it so hard for their customers to play the game. Come on Ubisoft, your rules to protect from piracy just make it harder for the people who actually buy your games.
Other than that, you should just get this game, no matter who you are, because it is just an innovative, great game.