After surveying almost 1,000 covercase customers and testing close to 100 iPhone 6 and iPhone 6 Plus cases over a period of about 4 months, our current pick for the best all-around case is the Renegade Case. The Renegade line has protected several generations of iPhones and has a reputation for providing solid protection and a good fit at a great price. It's slim but still very protective.
From our perspective, a respectable degree of shock absorption is important, as is a tight fit. The case should cover as much of the iPhone's body as possible, including a raised lip around the screen to keep the display from getting scratched when laying flat on a surface. The best cases also offer button protection with great tactility, mimicking (or in some instances even enhancing) what you'd feel with a bare iPhone.
Renegade case ships with full glass screen guard although not the same level of protection as the SumoGuard but it is still a great tempered glass that comes free with the case.