The provider is the one that is responsible for your mobile networking experience. Without the services of the provider, your fancy phone is more or less useless, and can be used as a paperweight or a doorstop.
The four largest carriers in the US are Sprint, Verizon Wireless, AT&T and T-Mobile.
There are features and characteristics that are common, but the special features is what often differentiates them.
T-Mobile
The smallest of the 4 largest carrier. T-Mobile uses a High Speed Packet Access technology that is believed to be as fast as the 4G LTE. They do not carry Apple iOS devices such as the iPhone, but offers Google Android phones, with an expanding lineup of smartphones.
You can opt for unlimited data and voice plans. Options for owing the phones include an outright purchase, or you can pay for it in 20 monthly instalments. T-Mobile is a subsidiary of the German telephone giant Deutsche Telekom, and has extensive international roaming capability. They also offer prepaid plans, or plans that include friends and family.
Verizon
Verizon Wireless is the largest wireless provider in the US. The company operates an extensive 4G LTE network, and an equally extensive lineup various feature phones, and smartphones. The company was born after the industry was de-regulated in 2000, with a merger between Bell Atlantic and GTE Wireless .
In addition to offering prepaid plans, Verizon offers a “share everything” plan with unlimited voice and data transfers for a multiple number of devices. The prices rise as the usage and the number of enabled devices increase. Verizon remains one of the holdouts for CDMA, and coverage may be limited internationally, but it also offers handsets with both CDMA and GSM capability.
AT&T
As the 2nd largest carrier in the United States, Verizon Wireless, provides an ever expanding 4G LTE network. The company offers an expansive lineup of GSM devices, along with shared and individual plans. They also offer tiered payment plans for use with smartphones. along with prepaid plans.
Through the use of the GSM technology, AT&T is able to offer extensive international roaming capability.
Sprint
Sprint was one of the first carriers to offer 4G network technology through the Worldwide Interoperability for Microwave Access technology. The standard was designed to deliver data at up to 30 to 40 Mbps. The company is slowly transitioning to 4G LTE. The lineup of handsets, may not be as extensive as other providers.
Sprint offers handsets that can operate with both CDMA and GSM technology, although international coverage may be limited. The company offered both pre-paid and family plans through it lower cost subsidiaries and in partnership with Virgin Mobile.
You also have the option of unlimited voice and data plans.
U.S. Cellular
U.S. Cellular serves 26 states in the Northeast, the Midwest, the Northwest and the Southeast. Company offers a selective variety of Android phones, that are run on its LTE network that was launched in 2012. The company offers some unique plans, that allows customers to redeem points earned toward the purchase of new phones or accessories, and digital content.
US Cellular features both unlimited voice and data plans, and also provide tiered payment plans that include friends and family. International coverage is limited as the company is a CDMA carrier., which is limited in international scope. The network is not particularly extensive, but because of arrangements with other partners,US Cellular can provide roaming capability for nationwide coverages.