I have 2 of the of the old style 'D' size Mags and two 'C' size Mags all converted to run on LED's. Three have Terralux conversions and one 'D' size uses a Malkoff Drop in. One of the 'C' size lights uses a Terralux drop in powered by 3 x lithium C123's. This makes a great lightweight flashlight which is reliable and pretty darn near indestructible. The performance and beam qualities whilst pretty poor are a major step up from the incandescent originals. The Malkoff conversion sits in the car as a back up/emergency light and compliments the engineering of the original Mag with a simple but effective dropin which being a Malkoff I can completely rely on. However, having said all that it is my humble opinion these lights are not effective or useful in your line of work. Many people on hear will swear by this and that light but as you might have to trust your life to it one day remember that quality costs and even then nothing is 100% fail proof! For a primary light there isn't much out there that is rechargeable at the moment that I'd be happy to recommend. Unless you are happy with only one light (and that is a risky strategy) then you need two at all times. 1) Your primary, which can be anything you want and 2) a secondary back up which obviously shouldn't take up too much real estate on a belt. Read plenty of threads on here about various manufacturers and lights, ask questions and compare beam profiles and reviews both on here and on Youtube. Remember, that you need to equate into all of the above quality, reliability, serviceability and warranty before you commit your hard earned cash. Good luck and let us know what you decide?
i feel they where outclassed long ago by smaller more efficient and brighter LED lights and where sadly left to gather dust however i eventually decided on a whim to buy a Terralux LED upgrade bulb for my 6D and it was very effective as an upgrade to the incandescent bulb giving much greater light output with increased runtime but for me it was too little too late. 
