What is the difference between F350 & D838 topic

Hi,

What is the difference between F350 & D838 ? What is the frequency for F350 ? is there a difference in performance between the 2 models?
I am from Egypt and wanted to buy the D838 from eBay but there is someone in EGYPT who want to sell the F350 so i want to know is there a difference or is it better to get the D838, there is no 4G in my Country but i think it will be available in 2015, thanks.