Yea, it sure was gruesome.

It's funny, because knowing Vito's personality, soft spokeness, and calm manner, even during that scene, it seems he calmly slices the enemy up.

We see Michael raging mad, and even tho Vito might have been raging mad, he doesn't show it. I'm sure this is why, or at least part of why, Vito was a more likeable character than the one Michael had become. People who knew Vito may have feared him, but most respected him, whereas Michael was only feared.
TIS
PS, Which, by the way, that would be a good TB question if not already discussed. Who was the most likeable real life Don, if any. Wasn't the Teflon Don known as charming and likeable????