Fixed focus lights are for those circumstances when the operator's focus should not be bifurcated. Certain occupations lend themselves better to this application. I prefer the focusable rechargeable lights for general application when I need a flood light for sustained periods. The Ultrastinger focuses into spot mode better than flood. This is the reason that I have retained usage of the Maglite Magcharger.
The Ultrastinger should be shorter and its lamp assembly permanently fixed into spot mode. The Stinger HP, with its rear switch, is a better configuration. In due time, when users realize the benefit of the Stinger HP, it should outsell the Ultrastinger.
This is the reason that the Streamlight SL-35X has not attained the popularity of the SL-20-Series. The 35X is just simply too long for the intended application. I a few years, the Ultrastinger will supplant the 35X. The Stinger HP will eclipse the Ultrastinger and will be what the Surefire 9N and 9AN aspired to be and the 10X will never become - a rechargeable, affordable tactical light that will also serve for general duty applications.