If you were someone who had logic and reasoning you would either:
1. Search the web
2. Ask the locals
3. Do a cost/benefit analysis
If you are Bijal or Meghana, you would base your decision solely on who has the best advertising =).
Check out these awesome ads by Vodafone (aired during Twenty20 IPL Cricket matches). I can never understand the commercials here because they are in Hindi, but these are pretty self-explanatory. My two favorites (out of the ones I've seen) are below: