Kia K8 vs Hyundai Sonata: Which One Should I Choose?

I'm torn between the Kia K8 and Hyundai Sonata, both of which seem to offer impressive features and performance. The K8's sleek design and advanced safety features are attractive, but I've also heard great things about the Sonata's comfort and value. Has anyone compared these two models or have personal experiences with either that can help me make a decision?