Well, judging by the titles of the responses that have come before me, I have chosen a well-trodden path to talk about, but it's the only question that came up repeatedly for me as I was reading, so I'm going to write about it anyway and hope that some kind of original thought manages to creep its way in somewhere.
It's a popular theme for science fiction writing and film: which to choose, grim reality or blissful illusion? Somehow, the message is nearly always "choose reality" â€“ Snow Crash is the first text I've come across (though I do not claim to have a comprehensive view) that is somewhat value-neutral on the subject. I say "somewhat" because the two main characters advance such polar opposite viewpoints, both of which seem equally appealing.
Hiro is in control and has power in the Metaverse; he is a "warrior prince" in the Metaverse (63). He is not totally sold on reality, either, saying "when you live in a shithole, there's always the Metaverse" (63). Y.T. has a similar kind of control and power in reality; she is pretty much autonomous and is almost always in control of her body and her fate. She has no qualms about entering into the Metaverse only as a black-and-white, something aficionados of the Metaverse cringe at, and criticizes Hiro at one point (though I cannot find the citation now, of course) for spending too much time there.
Several months ago, a friend of mine posed this question to me: If you could have a spouse OR a Hobbes (of the Calvin and Hobbes variety), which would you choose? It was supposed to be a light question to keep the conversation going, but the ensuing discussion went on for hours. The advantages and disadvantages of having a spouse are pretty obvious, so I will pass over them for now. Hobbes would be the perfect best friend â€“ you would have a complete and total understanding of one another, and you would be guaranteed to never meet anyone that could even rival Hobbes for fulfilling interaction and conversation.
However, for everyone else, he's imaginary. You cannot share him with anyone else, so you effectively have to choose between a perfect friendship with one person, and the rest of the world, which does not contain anyone who could be your friend in any real way (they will always pale in comparison to Hobbes). Compare this to Hiro: does he choose the U-Stor-It or the Metaverse, a reality that he can manipulate and control, a reality more perfect than one he could realistically attain in the real Los Angeles?
The book's answer is ambiguous, which is a bit of a cop-out, but does prove what a complex question it is. Snow Crash seems not to be arguing for one kind of reality over another, but a balance of the two. Hiro criticizes those who never totally leave the Metaverse, describing the gargoyles as "the embarrassing side of the Central Intelligence Corporationâ€¦they serve as human surveillance devices, recording everything that happens around them. Nothing looks stupiderâ€¦[it] mark[s] the user as belonging to a class that is at once above and far below human society (123-124). However â€“ lest readers think they have landed on a solution to the tension â€“ Hiro becomes a gargoyle later in the book, and that unquestionably saves his life.
I chose Hobbes.