Would you ever choose to be a host?

It's 5:30 and I'm watching stargate sg-1 dvd's. It was an episode about the Tok'Ra.

I'm wondering that IF this was possible, if these things existed, would you agree to be host to one?

-The Tok'ra are basically parasites.
-They enter through the mouth and latch on to your upper spine / into the brain
-You would split control of your body with it, switching between you two.
-It has the power to completely take control of you, but chooses not to.
-Your life expectancy will be about 200 years.
-When the symbiote is in control, you basically can see everything but you aren't in control.
-You have a perfect immune system. basically no disease can kill you, and your wounds heal in no time.