I know I'm a little late on this one, but I just caught the movie on HBO. I was hesitant to watch because of "that scene," but in reality "that scene" is only a small percentage of the screen time. It's easy enough to look away if you're really grossed out (I made myself watch).
From a story telling perspective, I was truly blown away. I HATED Slumdog Millionaire, Danny Boyle's last movie. I thought it was obvious, contrived, and not that interesting visually. 127 Hours was the exact opposite. The movie was riveting, filled with great imagery, symbolism, and even some deep philosophical thoughts. Really, it was about as close to a visual novel as I've seen in a long time. I don't want to get into the details of that - it's best if you experience it for yourself if you haven't already, but it truly is well done and smart.
Franco's performance has been much discussed and I have nothing to add except I'm no longer so sure Colin Firth should have won that Oscar for best actor. He was exceptional.
The movie is similar to Castaway, but eliminated what I thought was the fatal flaw of that movie - the opening in the Tome Hanks movie was too long - it took him a quarter of the film to get to the island. With 127 Hours, after a brief prologue that resonates symbolically throughout the film, it gets right into his trauma.
I highly recommend the movie. If you are squeamish, you'll have to close your eyes for about three minutes, but don't let that deter you.