I've completed it 3 times and all 3 profiles are rich and own most of the properties and are all masters of melee and 2 are masters of all 3 skills and I still like to play it.
First time took me a few weeks although I was still learning. Second time through it took I think 1 weeks and then third time around 2-3 days without intense playing.
Plenty of hours of gameplay; plenty of abilities to learn; so much to find in the game.
Storyline was okay; the game was a bit easy although unlike in Fable 1 in which if you die in the middle of a mission without a res potion you have to restart, in Fable 2 if you die in the middle of a mission without a res potion you only get a scar and lose all exp that is on the ground and then you can get right back up and keep fighting.
I found the ending cutscene a bit too long