1. Gigabyte Z170X-UD3 --> not only looks the best, appears to be good for some overclocking
2. Asus Z170 Pro Gaming --> less internal USB3 ports than the GA
3. Asus Z170-A --> more fan headers than any other board but only 8 phases. also an older soundchip.
4. Gigabyte Z170XP-SLI
1. Gigabyte Z170X-UD3 --> not only looks the best, appears to be good for some overclocking
2. Asus Z170 Pro Gaming --> less internal USB3 ports than the GA
3. Asus Z170-A --> more fan headers than any other board but only 8 phases. also an older soundchip.
4. Gigabyte Z170XP-SLI
If you are comparing with Asus Z170-PRO GAMING then compare with Gigabyte Z170X-GAMING 3
or Z170X-ULTRA GAMING. Z170X-ULTRA GAMING is one of the best in this range.