The Sea Inside and The Diving Bell and the Butterfly are similar but also very different to one another. One similarity between the two is that both movie and book include a person that is quadriplegic. Also in both movie and book, they were older guys and they both still had family. In The Sea Inside, Ramon did something that had a consequence of him being quadriplegic (diving into shallow water). In The Diving Bell and the Butterfly, Bauby's symptoms came out of nowhere. Also Ramon wanted to die and he killed himself and Bauby died cause it was his time. Lastly, a difference between the two was, Ramon was able to speak and see and Bauby was able to just blink.
The one I believe was more powerful was The Sea Inside. The reason I believe this was more powerful because it talks more about his problems he has rather than random dreams he has. Also it is more powerful because he actually kills himself so you see how bad/hard his life must be in order for him to WANT to kill himself.