I haven't. Is Unbreakable unwatchable?
Yes and no. It's still quite fun, and Willis doing his understated Willis is great, and Sam Jackson is ageless, and the idea of the pre-comic-book-movie-flood origin story is good. The best part of all is that it's a self-contained origin story that doesn't require a knowledge of the greater, expansive, universe.
But... It does feel a little bit like returning to Star Trek TMP now, after 40 years of the franchise exploding and fighting wars and moving at warp speed on a motorcycle to heavy metal music. So, basically, returning to your comment above about the tidal wave. The old resort has been rebuilt, and it's still fun and pretty but, at night, as you lie on your silk sheets and watch the bamboo fan lazily sweep around above you, you can't help but remind yourself that 150,000 people died in the tidal wave last year.