Xiaomi scooter 4 pro vs pro plus July 8, 2019 16 32 64 128 Xiaomi electric scooter 4 pro vs 4 pro plus Xiaomi scooter 4 pro vs ninebot f2 plus Xiaomi scooter pro 2 vs 4 pro Xiaomi pro 4 scooter review Xiaomi pro 2 vs pro 4 Xiaomi scooter pro 2 vs 1s Xiaomi scooter 4 ultra test