The Motorola Moto G is a value priced handset that runs Android 4.4, offers a 4.5 inch screen with 720 x 1280 resolution, and is powered by a quad-core Snapdragon 400 processor with a 5MP camera around back. Ironically, the phone was designed to compete in the entry-level niche where the Nokia Lumia 520 has been cleaning up.
The Windows Phone powered Nokia Lumia 520 offers a 4 inch screen with 480 x 800 resolution, and is powered by a dual-core 1GHz Snapdragon S4 Pro with a 5MP rear-facing snapper. The ZTE Sonata 4G is an Android model with specs similar to the Lumia 520, except that it includes a faster dual-core 1.4GHz Snapdragon S4 and has twice the RAM at 1GB.
Aio offers three plans. The basic plan is $40 a month with unlimited talk, text and data (500MB of high speed data). The smart plan is $50 a month for unlimited talk, text and data (2.5GB of the high speed stuff). For $60 a month, Aio gives you unlimited talk, text and data (5GB high speed). If you agree to an Auto Pay program, you can get a discount from the carrier.
The ZTE Sonata 4G is now available from Aio
source: Aio via Phonescoop