.io as those who own .co loose traffic to .com. Those who are not domainers will often think it is a gtld or email mistake.
.io is also popular in the tech scene and there is also a lot of development in the .io extension compared to .co. There is also a lot of LLL.co dropping every day.
I like .CO myself as well. But, for the location you're trying to target EU might make more sense. Or, better yet .ie/.uk/.co.uk might be better overall for that..