I used the Otterbox Commuter series on my S4 and it worked very well.

However, when I bought my S6, the only ones they had in the store were all black, so I wanted something with a splash of color and decided to hit Amazon and found my Spigen case with a clear back and a bright blue outline around the sides of the phone. It has held up great over the past 3 months since I bought it and I really like the color that it gives my phone. The shade of blue actually matches my car as well, haha, which was totally unplanned.