Apart from the keyboard layout (no £ or example) another difference is the local salex tax, that's lower in the US.
You have to pay customs at the UK airport for any item over £390. https://www.gov.uk/duty-free-goods/arrivals-from-outside-the...
You have to pay customs at the UK airport for any item over £390. https://www.gov.uk/duty-free-goods/arrivals-from-outside-the...
Only if you declare it ;)