I see no good reason to believe it is a good normative theory
How are you going to evaluate a normative theory, except by comparison to another normative theory, or by gut feeling?
'Gut feeling' is pretty much how I am evaluating it (and is a normative theory in a sense - what is good is what your intuition tells you is good). Utilitarianism says I should value all humans equally. That conflicts with my intuitive moral values. Given the conflict and my understanding of where my values come from I don't see why I should accept what utilitarianism says is good over what I believe is good.
I think an ethical theory that seems to require all agents to reach the same conclusion on what the optimal outcome would be is doomed to failure. Ethics has to address the problem of what to do when two agents have conflicting desires rather than trying to wish away the conflict.
My girlfriend/SO's grandfather died last night, running on a treadmill when his heart gave out.
He wasn't signed up for cryonics, of course. She tried to convince him, and I tried myself a little the one time I met her grandparents.
"This didn't have to happen. Fucking religion."
That's what my girlfriend said.
I asked her if I could share that with you, and she said yes.
Just so that we're clear that all the wonderful emotional benefits of self-delusion come with a price, and the price isn't just to you.