The STRIX 1080 is a generation leap in every sense of the word. The card offers significantly higher performance while consuming less power. NVIDIA's reference GTX 1080 is excellent, and ASUS' offering builds on that with a custom cooling solution, RGB lighting, and easy overclocking options.
If you're running a 1080p or QHD single-monitor setup, the STRIX 1080 is overkill, and you'll be better served by the GTX 1070. If you're looking for a card that can handle 4K and VR, look no further.