I have net10. I love it total worth it for me. To be frank Net10,straight talk, and tracfone are the same company. So there all the same company they why all the different names. GO for the one you like this is why I got net10 over the others,
Straight talk is only sold at walmart that goes for the refill cards also.
Net 10 and Tracfone cards and phones can be bought at almost all stores even small stores like local places.
Also if your in a gsm area and have a gsm phone that works with att or t mobile one you can by a bring your own card, This card net10 or straight talk is only sold online on there sites, How it works you buy the card I got this service and then use it in your own phone any type of gsm phone will work. But you must sing up or only use the unlimited plan. This is cool for about 50 bucks you get unlimited everything for 30 days.
I got a att android phone I use with net10.
I been on net10 for about 2 years and love it to death,
Net 10 bring your ownhttp://www.net10sim.com/
ST bring your ownhttp://straighttalksim.com/