Thanks to the dual-part system, the Reflex is the easiest to install of any OtterBox I have used. I decided to forgo the screen protector as I've never had much luck installing those from OtterBox and the included one doesn't look to be any different.
To install your iPhone 4 in the Reflex case, just separate the two parts, slide the phone into the top portion then slide the bottom part on until it locks in the middle.
It's worth mentioning that I had to remove my full coverage Invisible Shield in order to get the phone into the case. I tried with the shield in place but the back cover started to peel up along the edges. I could have possibly kept the front shield in place but I decided to remove both to achieve the best fit.
Usage and a conclusion are just ahead.