I have tata photon plus it gives speed from 256-400 kbps only when I raised and issue I was told that this the correct speed for photon plus. They say in real world this the correct speed. It should be made mandatory to for companies to provide the average speed and the minimum guaranteed speed of devices when they advertise not the max speed which is never the case in real world.
TATA Photon are the worst I have used.