I voted 6, as it just beats out 5 in a very close contest. Either way, I personally regard the idea of hanging onto a human body as unnecessary sentimentality, especially if the rewards for discarding it are so great. I also have some rather long term plans for my consciousness (should technology allow it), so all my decisions on this are considered with the very long term in mind.
The benefit of 5 is that grants me much of what I'm after; longevity, improved mental capacity, and physical versatility. However, the main reason it can compete with 6 is that whilst extremely transhuman, I am still of a similar kind of consciousness as I am now. that means I can still view the universe with awe, be excited by the mystery of exploring it, and perceive it all from a personal level.
However, to become 6 represents something altogether entirely different; to become a mind so different from my current self, to be able to understand concepts far beyond what the human mind is capable of, and to rise above the petty, arbitrary mechanisms that govern a human-like's life is something I would gladly sacrifice my humanity for. Whilst being human or human-like offers an irreplicable experience, I view it in an entirely pragmatic manner; it certainly is not a cornerstone to my beliefs, or sense of identity.