I do consider myself fat (6', 270lb), yet don't find the seats uncomfortable. Different, yeah. Unexpected. Certainly more snug than anything else I've tried, including the GTI.
But not uncomfortable. By the third test drive, I didn't even notice them.
And it's nice not having that urge to brace a knee against the door or console to stay in place during a turn.
I don't have enough time in them to know what it'd be like after a few continuous hours.