Hi,

moving to US soon. How have people found the culture shock between UK and US?

That would depend on where you are moving from and to, e.g London to NYC, no big deal, London to Arkansas, ouch.

It's been a while since I first moved the USA, which was way back in 2001. (I'm no longer there)

First observations.

You generally never pay the advertised price for anything.

You will be absolutely stuffed until you get your Social Security number, despite most locals saying it won't be a problem, when you explain you've not yet received it.
It's a country where you really need to be part of the system. I can rattle off my US SSN more readily than my UK NI number.

I wouldn't consider any of these things a culture shock.

What used to amuse me the most, was the complete lack of awareness, that some people have, to anything outside of the USA.

Look at the current meltdowns in the USA after the outcome of the recent election...