MediaTek Helio A25 Advantages
More modern manufacturing process (12nm vs 14nm)
Lower TDP (5W vs 7W)
Released 3 years and 2 months late
Samsung Exynos 7420 Advantages
Better graphics card performance FLOPS (0.1976 TFLOPS vs 0.0416 TFLOPS )
Larger memory bandwidth (24.8GB/s vs 13.9GB/s)
Higher Frequency (2100MHz vs 1800MHz)