OOTP is a decent comparison, yea. Probably as close as any other game I can think of, anyways. Football Manager has completely taken over my life. Any free time that I have goes straight to FM, and its been great :D
Ugh thats the worst. Happened to me with College Basketball a few months back. Wanted nothing more than to play College Hoops 2k8, but I couldn't find it, then no gamestop or store in the area had it. I was miserable for a bit there.
I bought FM13 with steam so I it was an automatic update, but you should be able to find one easily.
I love FM, my favorite part is setting the team up in the first transfer window, buying/selling/loaning players, imagine a formation, forming your staff, scouting players/rising stars, and then watch how good your team is and the fact you can tell it's your team.
But I never had the patience to go more than 3 season, after that I want to try another team with others players and so on.