I had chinese unit as RNS 510 replacement in my golf, and it wasn't worth it believe me.
First it was very slow, second integration with vehicle was 0, i could not use st wheel control, MFD. Third, support from China/UK was rubbish.
I had it in my car for couple days, and I sent it back.
If you want aftermarket unit go, for Pioneer, Kenwood or any other reputable manufactures