Is the latest FM better than the last couple of them? I'm still a fan of CM03/04, I've found the last few getting a bit too indepth. Frankly I might as well train to be a football manager IRL with the amount of tiny little decisions that need to be made about every match. I know it was never a boot up and play sort of game, but I think FM07 got a bit too detailed for casual players.
I think it's great, but then again I've liked and owned every version since CM96/97. I don't find the tweaking too much of a problem - I usually just find a formation that works for me, set it up for home/away games (maybe a couple of other variations - like an all out defence) then I just change things during the game depending on how it pans out. I don't get all these people who say you've gotta make loads of little changes before each game, once I've got players who fit my formation it's normally fine.