The Samsung Epic 4G comes loaded with features. It uses Sprint's CDMA network, as well as the new WiMax 4G network that they are deploying. At an extra cost, the Epic 4G can turn into a wireless hotspot, similar to the Verizon Fascinate that will be released soon.
One interesting feature that the Samsung Epic 4G has that its brethren does not, is a front facing VGA camera. This camera, in conjunction with a Qik account can be used to perform video calling. Each person has to have a Qik account, whether it be on a phone or a PC. Sprint's WiMax network is fast enough to stream the video fairly smoothly, but using the 3G network does cause a bit of choppiness. It's best advised to use the camera on WiFi or on Sprint's 4G network. These video calls are free, unless you want better resolution which costs a bit of money.
The Samsung Epic 4G also has a 5 Megapixel camera with LED flash. This LED flash is extremely helpful, considering the other Samsung Galaxy S phones do not have flash. Instead of having to rely on a fairly useless 'night mode', you can use the LED flash to take pictures in the night. It's quite interesting how Sprint's version of the Samsung Galaxy S is the only version that has LED flash.
Beyond the cameras, the Samsung Epic 4G comes preloaded with the usual Sprint prepackage, including Sprint Zone, Sprint Navigation, Sprint Football, Nascar Sprint Mobile, and Sprint TV. Of course more applications can be downloaded using the Android Market.