And that's fine, I accept that after giving it some thought. It's just...well...Inception
It doesn't matter if it's still spinning or not. Whether it's reality or not is up to you. What matters is that he doesn't care, he's reunited with his kids, and he has let go of his guilt for Mal's death.
...it's the goddamn Total Recall ending all over again. It'll be that little nagging voice in the back of my head, wondering which way it went. Ditto for Pan's Labyrinth and whether it all happened or if the fantastical stuff was all in her head.