The galaxy s6 edge and galaxy s6 share alot of the same basic features. The screen size and resolution are the same. They both have the same cameras on them, and they also have the same processors. Where the galaxy s6 and galaxy s6 edge differ are in design, weight, battery size, and software features.
The galaxy s6 edge weighs slightly less than the galaxy s6 at 4.6 ounces, but is also a bit thicker because of the curved screen. The galaxy s6 edge has a slightly bigger built in battery at 2600mah which actually does give it a little bit more battery life. Not saying its anything major but there is a slight difference.
Other than that the last major difference in the galaxy s6 and galaxy s6 edge would be the extra software features on the s6 edge. Since the galaxy s6 edge has a curved screen there are some cool futuristic like features that arent a neccesity but there is a coolness about them. With the galaxy s6 edge costing a bit more then the galaxy s6 it would be worth it to just go with a galaxy s6. Like we said all the basic features are the same, and they are both made with glass and aluminum.