The DEWALT DCG409 & DCG416 Angle grinders have been out for about 2 years. DEWALT has added the DCG409VSB & DCG416VSB Variable speed models to the new tool lineup recently and they are everything you would expect from a well-balanced 20-volt angle grinder.
These new angle grinders are packed with technology that helps them detect safety hazards and keep the user safe. The best part of the safety is that it does not falsely detect these conditions in normal use. While the electric brake could react slightly faster, it is still working pretty well for the designed use.
The variable speed dial allows the user to choose between 3,000 and 9,000 rpm. I do not have to tell you that this is awesome when working on more delicate projects.
FlexVolt Advantage does not mean this tool has 60-Volt FlexVolt Power. The PowerStack (20-Volt)battery is not more powerful than the FlexVolt (60-Volt) batteries at this time. This just describes that the tool is electronically designed to get the most power out of each battery that is used on the tool. If the tool can draw more amps from the battery, it will. There is a lot of confusion surrounding that wording.