The virtues of modular lights where you can just drop in the pill of choice have been expounded upon in numerous pages. The ability to have a host where you can drop in a high intensity spot light pill one minute, a malkoff flood module the next, a warm tint unit, a multi output level unit really shouldn't need explanation. The whole concept of having battle spare modules for the host and mixing and matching should be reason enough.
I have had up to 6 Solarforce Hosts and a SureFire 6P. I have sold some to friends who just had to have a custom built MrGman special. I have extension tubes, pressure switches, forward clickies the new 18650 sized host and extension, so the combination of mix and max is very wide.
I have had no reliability issues with lights or modules that were not an actual failure straight from the get go. Meaning a pill here or there didn't work right when it first came in, but I got a quick free replacement, and the ones I have work well. I have dropped several over at the gun range concrete floor, I have a few fall off my mountain bike while I was working on the mounting system to paved street. Beat up the bezel but the light just kept going.
The real problem here is once you start there is no end.
For instance I just got the Solarforce "Lantern Head" that screws on to the end of the bezel. Take the assault crown off and the glass out (just another wasted drop in light output that is no longer necessary), screw on the Lantern Head and voila, an overhead camping "torch" with 360 degree output. I have a Malkoff M60 driving it. I should take pictures its so nice. I put the Uniq Continuously variable tail cap on it and now its a fully dimmable camping Torch.
Now you can get ridiculously powerful P7 or MC-E pills to put into these things, what's not to like.
