中途半端なレビューよりこれ見て自分で判断しろ

Dudu7 = 888 platform
Mekede M7 = 880 platform

The main differences are....

Capacitor
888 - 10,000 μF
880 - 6800μF

DSP audio processor:
888 - AKM7739 (DTS)
880 - AKM7738 (DTS)

Amplifier chip:
888 - TDA7808 (TDA7803 in some units)
880 - TDA7851

GPS
888 - Dual band
880 - single band

Dudu7 - Qualcomm 3031 bluetooth chip
Mekede M7 - Realtek RTL8761BTV bluetooth chip

888 also has better heat dissipation.
888 also has a gyroscope built in

Edit: added a photo with comparison specs.