Thank you, everyone, for the warm welcome!
yboris, I agree with you that subjective experiences are probably the only items of value in the observable Universe; my main objection to the "experience machine" where you get hooked up to a Matrix-like dreamworld where everything is awesome all the time (including whatever degree of challenge and suffering you turn out to enjoy) is that it wouldn't work in practice. If you assume away that objection, and credibly assure me that it really would work, and that everyone who wants to plug in can do so, for as long as they like, at zero risk, then I would plug in without hesitation, even if it meant that, e.g., my "objective body" would wither away or send out pain signals that would never reach my awareness.
That said, I don't think that your formula "preferred subjective experience" gets around my concerns about preferences and pleasures. Maximizing pleasure is unwise because there are things we want (and ought to have) that go beyond pleasure, such as authentic connections, challenge/struggle, the freedom to make decisions that affect our futures, etc. Even if we find aspects of these things pleasurable, I think it is pretty clear that one could imagine a scenario in which eliminating them would be necessary to truly maximize pleasure. For example, a cocaine high with no side effects that could be sustained indefinitely, or a mind that was reduced to orgasmium, would not allow much room for complex phenomena like relationships, struggles, or freedom. But if we really want to maximize pleasure, we shouldn't care about that, and we should just all become wireheads.
Preference-satisfaction does a little better than pleasure, but people often have very unstable preferences, to say the least. Between hyperbolic discounting, priming/anchoring effects, loss aversion, framing biases, selective memory, motivated cognition, and plain old ignorance about what is like to have a given subjective experience, it is hard to say that humans even *have* preferences over the set of reasonably common lifestyles. Obviously we prefer a good square meal to torture, and prefer to save an apparently innocent child from drowning in front of us rather than to read the recipes column in the newspaper, but for any serious moral debate, the answer you arrive at will often depend on which equally plausible meaning of "prefer" you choose to deploy.
Arepo, hope your headache goes away soon.
Pat, you're very flattering, but I couldn't help noticing that you are posting from Alaska. If your defective boat injures you while accidentally drifting 4000 miles down the Pacific coastline, I will be honored to serve as your personal injury lawyer.