The hardware of the two variants is identical.
The only difference between the EU variant and the U.S. variant exists in the software settings. However, as a customer, you can change these settings over to the other variant (in both directions) and you can repeat the process as often as you like.
Due to the settings, the U.S. version has a higher output level, which means that the volume is still high enough on headphones with higher impedances. However, headphones of all impedances can in principle be used on both variants.
The question of individual suitability applies only in relation to the required sound pressure level.
Completely apart from this setting, there are many advantages to a very high-quality digital-to-analogue converter.