Which DEWALT® Drills are best for mixing Grout, Mortar, or Drywall Joint Compound?

For mixing "mud", you need a drill with a low maximum RPM, but powerful. In the cordless line, the DCD130 60V MAX Mixer/Drill is made specifically for this application:
User-added image
If you prefer the corded variety, we suggest DW130 seen here:
User-added image