A translation in English could be as follows.

• What about you, how did you like (it) living in the United States?

The second “vous” is what elicits “what about you” in the English. A sentence where such a repetition occurs entails a special context, that is a context in which the person talking has either been asked the same question (less the repetition of “vous”) or in which some people were mentioned about whom the same question was the locutor’s topic of conversation prior to the asking “What about you…”. The repetition, in this precise case, is a way of saying “now we have their/my opinion, what is yours?”.

This question in French would often be shorten as “Et vous ?”, just as in English you might say simply “What about you?”.

Your questionh has two parts.

The translation LPH offers is perfectly fine. I think the pronoun repetition (for stressing purposes) is a typical French construct that should usually be dropped in English, especially in an informal context:

Did you like living in the United States?

As for the translation you found, it is a correct French sentence but an incorrect translation. There is no indication of any “better” in the original sentence, may it be directly (mieux, meilleur) or indirectly (préférer).

This extra vous is just reinforcing the first one, just like would be the Spanish:

¿Te gustó, a ti, vivir en EE. UU.?

or

¿Le gustó, a el, vivir en EE. UU.?

Note that I more often hear that kind of questions with a preposition, like in Spanish:

Est-ce que ça vous a plu, à vous, d’habiter aux États-Unis ?

In English, a similar emphasis on the pronoun could be:

You, did you enjoy living in the United States?

Also, this sentence feels like a rhetorical question to me, especially with the extra vous. Where the person asking the question already knows the answer, but just wants his interlocutor to say it.

I think the translation of LPH is correct, but doesn’t really express the rhetorical question.

But I’m probably overinterpreting it, and his translation is perfect 😉 .