Why go to extremes? I wouldn't want immortality, but living to be around 150 sounds good, provided my physical body would be in a good condition. But then again, even 150 is too long, there could be disastrous consequences for the planet if everybody got to live that long.
I'm sure if immortality were a reality, it would only be available to the very rich, like the Rockefellers, and they would probably take it, so that they can continue ruling the world as they please. For the regular people like me, who actually think about the consequences and don't have a world domination agenda, immortality would be pretty undesirable.
Do you offer a trial period? Like let's say, 100 years? I'd take that, see how it goes, and if I still want to live past that. Call me to set the price