Real Time GPS Tracker Module Selection

I am planning to make a real-time GPS+GPRS vehicle tracker, that sends the location of a vehicle realtime to an App. Something similar to an UBER. I am having trouble choosing one of the following 2 modules:

  • SIM808 Module GSM GPRS GPS
  • Ai Thinker A9G Core Board Module Pudding Development Board

Which one do you think is more feasible in implementation and has better accuracy, and lifetime?

Can you provide links to those products, saves everyon having to do their own searching ?

There are quite a few ready built GPS+GPRS trackers available at low cost so why do you want to build your own ?