The right Yeerk would find me to be a very habitable host.
Let me explain: A Yeerk would pretty much know everything about me, and interact with me directly on the regular. Yes, I would be very distressed to find myself unwillingly colluding in the terrible and sometimes violent acts required in the expansion of the Yeerk empire, but... (Oh dear, I can't believe I just stuck a "but" at the end of that thought...)
Most days, between the horrible things, between the small but awful actions my body would take against my will to further a vast yet secret war of enslavement on all of my fellow humans, I think I would just find it reassuring to have an unlikely buddy up there, in the old noggin. I'm not a very decisive person. There would be moments when knowing someone else who is capable and focused has the reigns would be a great comfort to me.
But this is how most of these kinds of questions work for me. I usually assume I'd do the wimpy thing when faced with horrifying circumstance. Zombie apocalypse? Probably not Patient 0 or anything, but I'd be "converted" to Team Zombie pretty quickly, I imagine. I hold no illusions about saving the world. I have very few illusions regarding even living a "good life" (by my standards, which are high) as it is, possible horrible circumstance aside. That's part of the reason why I connected so much with Animorphs as a series; each of the main characters had huge doubts and none of them would have been successful on their own or arguably in a different configuration of resistance.
Harmless fandom question becomes depressing personal reflection!!