I have latex allergies, so my preference is pretty obvious.
But then, I'm married. I'm 99.9% sure my wife isn't going to give me a death dose, and for that extra .1% we both get tested periodically just to make sure nothing has been lying in wait for years.
I definately prefer bareback, although in this day and age it'd be a helluva risk unless you took serious precautions. Don't do it if you doubt that cleanliness even the slightest!