SH3 is one of the best value-for-money games I've ever owned. Ordered it on/around release day for only £17.99 - cheaper than most new games, presumably because it wasn't expected to sell quite as well as all the shooters and other mainstream games.
Of all my games, it's the one I always come back to for a long period even after a time away with other games. Normally I only return to old games for a brief time before I'm bored again, but with SH3 I often return and play it for a long time. Partly because it takes such a long time to play through
You don't get instant results; you only find satisfaction after a long effort that's played (usually) over several real-life days. And I like that. It's better than any instant gratification game.