The best plan would be the one that has the requirements for your specific needs. Coverage, price, features and phones are a few things to consider.
Not all wireless providers are equal and in many ways the least expensive is not always the best choice.
You might get a inexpensive plan that you may think it is a great deal but if your device does not work when and where you need it, the plan savings will not matter. Coverage is an important factor when looking in to wireless service, not all wireless providers have coverage and some may have coverage but some features might not work. A example of that is my Google voice application that I use to make calls and do texting. When coverage is minimal my text do not send or receive since the app is using data to send or receive texts. That’s one example but depending on what you are trying to do you need to make sure you get the right coverage in the areas you use your device the most. Another important feature for me is international compatibility (using my device in another country).
Last month I traveled to Trinidad and wanted to use my device in a couple of different ways. First I wanted to be able to land and call my friends so they can meet me at the airport, which was easy by adding the international roaming feature before I traveled with Verizon Wireless (call for rates in country of travel for voice, text and data). Secondly I wanted to use a Sim card from one of the local wireless providers in Trinidad to make calls locally which is a lot less expensive than roaming charges. Some of the world phones that Verizon Wireless provide already come unlocked so you can put a Sim card from a carrier overseas to make calls and text (data had to be used WiFi). I was using a Verizon Samsung S3 in Trinidad at that time a Samsung S3 MetroPCS or StraightTalk would not allow me to roam and I would have to get the phone unlocked to work overseas.
These are just some things to consider and when looking into a wireless service please make sure to discuss all of your needs to the wireless consultant so they may be able to direct you to the best services for your specific needs.