I have just bought a (Chinese) Vesta from Deniz Motor on the Baris Manco Bulevard in Calis.
Total price 2,250 TL for 150cc scooter, helmet, storage box, insurance, 2 years guarantee, road tax, etc.
Th guy is called Abo (Abdulah) & is extremely pleasant & helpful.
Regarding Chinese verses Japanese, you pays your money & you takes your choice. Yamaha = Rolls Royce, Chinese = Ford?