I P Daily on the MMM Forums has authored a "SuperGuide," but the latest version I could find on here was dated 2014. It's best to check out his blog at
http://www.techmeshugana.com/ My strategy has been:
1. Use a Google Voice / Hangouts main number
2. Use MintSim (prepay 12 months at $15/m, 2GB data) as my carrier
I am not a heavy voice phone user, and family & friends know my phone number may change from time to time as I tweak / change options. They always know I can be found at my GV number. (I also like the advanced GV features which allow me to provide different voice mail messages to different groups of callers. Friends get a message giving my travel details, while clients & customers get something more formal.)
MintSim is on the basic T-mobile network, and has limited coverage in the west. For example, there is almost no coverage in Wyoming, Montana, and western Nebraska. In these areas I use the wifi support of Google Voice / Hangouts.
Some have raised questions about the long term financial viability of MintSim, and are concerned that their phone number may be held hostage or lost in a shutdown. Using a Google Voice number as my primary mitigates this risk.
When traveling internationally, I rely on Skype Out for local calls over WiFi. If I must have wireless data when traveling, I will purchase a prepaid SIM. As an example, I paid about $35 US for a 10GB SIM when I was in South Korea earlier this year for 2 weeks.
