If you are on a us ansi keyboard and switch to a iso layout (most European layouts are iso) you have I believe two unreachable keys. And the arrangement of the others is slightly different you will have to adapt your muscle memory anyway.

Altgr-intl is pretty good for when you code and write English most of the time and occasionally need accented letters. If you need to write a lot in your native language it's better to get a local layout keyboard.