Stargate

I'd consider a Tok'Ra under the right circumstances. But never a goauld.

If I was terminally sick, yea. Basically the start of a new life, even if it's a dangerous one. Plus you always have a friend to talk to.

I would blend with a Tok'ra. Thousands of years of knowledge and experience, longevity and health, and still retain relative autonomy. Even if I'm only in control 10% of the time, with how long the lifespan is I would still experience far more life with perfect health than I could without a symbiote.

Maybe Tok'Ra but I would want to know them first and get along to begin with. That being said I would likely be ok with it being done all of a sudden to save my life. I mean I would be dead instead then and the tokra by and large have been alright. Hopfully I don't get a dick.