I was interested in buying an imported vita slim from Japan as it is cheaper than the European versions and they're sold in multiple colours but I was wondering if there are any downsides to owning an imported vita slim?
The X and O buttons are switched. Not the physical buttons, but X is to cancel and O is to confirm for the Japanese VITAS. --- Currently Playing: Outlast (PS4) | Zero Escape: Virtue's Last Reward (PSV) | One Piece: Romance Dawn (3DS) PSN: Spade21X - NFC: 5241 - 1904 - 3885
Generally in Japan and most other part of east Asia the face button O and X command function are swapped.
US/EU: X = Confirm O = Cancel JAP/ASIA: O = Confirm X = Cancel
However this ONLY applies to main system functions like the LiveArea menu screen. If you play a US (R1) region title it automatically revert into the "X = Confirm O = Cancel" even though the Vita region system is from Japan an vice versa playing Japanese region title (R2) on a US region system.
I can confirm this personally since I have the Japan God Eater 2 Vita console bundle and played US titles like Persona 4 Golden (R1) on it, the control assignment switches depending on the title which you are playing. The Vita inherited this same 'regional distinctiveness' from the PSP.