Service from Robokits is very good. I got the motor shipped to Bangalore within 1 day (to Bangalore).
Motor build quality is good and the encoder is as per specification. But the motor draws 1.15Amps at no load (not 600mA, as mentioned). The reason is that, the motor has lower back emf. In otherwords, the permanent magnet is not that strong on the motor and hence to produce some "x" power, it will consume more current and a similar motor, which has stronger permanent magnet. Hence the rating is "4". Also a slight loading of the motor will cause the current to increase drastically. But good part is that, this motor has higher speed (because of lower flux of permanent magnet).
Overall, I am satisfied.