I have both the RAM and the Kroll.
I ordered the Kroll from brightguy, and the RAM from outpost.com
Some observations:
The kroll is mostly plastic, with a nice rubber cover. You have to "push" the rubber coller into the base of the light as you are screwing it in, otherwise it does not fit in neatly. After installation, the Kroll feels very solid. You loose the flat end to stand the light upright with the kroll.
The RAM is all Aluminum with a plastic red "eraser sized" clickie switch. The switch is very soft (almost no restistance) to turn on, a cheap clickie pen has more restance.
My first RAM did not work. Others here have had similar failure rates with the RAM.
The Ram CAN stand on it's tailcap without turning on or off the light.
The replacement RAM tailcap did work, and works great to this day.
I left my light with my kroll laying around one day, and my dog found it, and chewed up the kroll portion of the light.
Do a search on Kroll and RAM TAILCAP to read more about these here on CPF. They have BOTH been discussed at length.
They are both good, but not perfect, and my two Opalec Newbeams have one RAM and one KROLL.
I would much prefer to use the tailcap that comes standard on a Brinkmann. (No, the tailcaps are not switchable, the threads are slightly different.) Overall, I much prefer the Brinkmann Legend AA, but that is a personal preference, as the mag is a very well built light also.