I prefer the (even creepier) Synthesis. There are a lot of arguments against it that I don't really have the energy to deflect, but in the end I just can't get enough of the EDI monologue. I have my reasons beyond that, so it's not like I'm sticking implants on every sentient creature in the galaxy because I like Tricia Helfer's line delivery. But when it boils down to Synthesis and Control being neck-and-neck as they otherwise are in my mind, I'll take EDI's monologue over Shepard's.
Also, Control's music piece is kind of unsettling. Now, people have countered with, "you find the music unsettling enough that it bothers you less than the free will implications concerning Synthesis?"
Why yes, as a matter of fact I do!