Qualcomm Snapdragon 439 Advantages
More modern manufacturing process (12nm vs 14nm)
Released 2 years and 4 months late
Qualcomm Snapdragon 625 Advantages
Better graphics card performance FLOPS (0.1248 TFLOPS vs 0.0432 TFLOPS )
Larger memory bandwidth (7.46GB/s vs 6.4GB/s)