In terms of build quality (interior & exterior), which is better? A Hyundai or a Kia?

It's almost the same but i will go with Hyundai

kia is better for sure despite them beeing the same company 

Both are the same in my opinion but they give KIA modern shape better than Hyundai these days  

Thanks for the invitation.

Kia is part of Hyundai group and both pretty much share the same interior and exterior materials, so I guess differences should not be significant or slightly in favour of Hyundai.

They are basically same company - they share 90% of all parts so its more a preference of design that will make the choice.