I cannot get behind a Milwaukee grease gun. I have one, but it only gets used when it's cold because the batteries last longer than my Lincoln 20V. I think it's rather clumsy, and takes steady pressure on the plunger when it's cold to pump.
As far as the lockNleak, no thanks. I don't know how some guys love them, and some hate, but they are definitely not for me. Tried 2 about 8 years ago. One lasted about 3 tubes, and not once had been stuck on a zerk. The second leaked after the second zerk. I use the standard Lubrimatic couplers. Buy them a dozen at a time, usually get through the season with that. I am considering buying about 1000 new fittings and swapping every single zerk in the fleet, and see if that stops the coupler issues.