On one side, we have typical prosthetic arms with five fingers, a complicated motor system and human resemblance. On the other side, we have this prosthetic tentacle with a one curl grip, simple motor and creeptastic design. Which is better?
I'm going with the tentacle. Not only because it can very easily do a variety of basic grips but because you can moonlight as Doctor Octopus and freak the hell out of your friends. Plus, having a tentacle on one arm and a normal hand on the other is much more versatile than just two hands, right? Anyone can have a pair of those.
Here's some of the grips a tentacle can do: