Given what most of you were saying here the other day, it seems pretty clear how you'll jump with this revised version of the thought experiment. But let's see what you think, and give your reasons. Does the "unnaturalness" of this scenario bother you? I don't mean that the scenario is contrived (though it may be) and unnatural in that sense; I mean the fact that it relies on high technology to make a life that is far longer than ever yet lived.
Person X lives for 75 years. Overall, she is very happy through that time. Let's express this by saying that she has an average happiness level of 8 (out of a blissfully-perfect possible 10) for those 75 years.
Person Y, thanks to advanced technology, lives for 150 years. For the first 75 years, she is just as happy as Person X: i.e., she enjoys a very good average happiness level of 8 out of 10 for those 75 years. In the second 75 years, her happiness drops off for various reasons (e.g. the technology keeps her relatively youthful, but it is not perfect so she gets more illnesses than she did during the first 75 years). Nonetheless, things continue to go pretty well for her, and she experiences a not-bad average happiness level of 7 out of 10 for the second half of her long life.
If I could offer you Person X's life or Person Y's life, which would you take? Person Y gets everything that Person X gets and more, but on average (i.e. averaged over their respective entire whole lives) Person X is happier. Which do you want?
Once again, please discuss.