Re: do i really need a Surefire Kroma MS?
I haven't played with a Kroma-Milspec yet (The passaround has me up in lonely Alaska as dead last), but I have played with the "civilian" version of the Kroma. I thought it was pretty seriously neat, and that can easily justify its price. It is a pretty seriously cool piece of technology.
On the other hand, it's designed for a pretty specific use, I feel, and that is hunting. Up here in Alaska, where almost everyone's a fishman or hunter, I'd say it's a tremendous value - you have blue for tracking blood, red for night-vision and two levels of white for your own general-use around the camp. Other than the "wow" factor of the Kroma, I admit to having a hard time justifying picking one up for general-use purposes (Then again, I use all my lights hard, and pick the feature-sets appropriately for that).
The "Milspec" version of the Kroma does not appeal to me as a light, although I still am looking forward to the passaround. The blue has heavy artifacting and the red is not as bright as the civvie Kroma; moreover it's few and far between folks that have a civvy use for the infrared.
As for the Guardian, the one I've played with has a certain "Wow" to it - especially on fresh batteries - but you run into the "not terribly practical" aspect of it as a general-use light; 20 minutes isn't that much runtime (It's rated at 500lm and on fresh batts is much higher; but my Mini-Mini HID does that for almost 45m on AW's new Li-Ion R123s and it's smaller).
The utility of the Kroma is very good, if you do things that leave you with a need for multi-spectrum light. The Guardian is probatly extremely useful in more "tactical" situations, where you need a retina-searing blast of incan at a second's notice - however, in my estimation (Being a person that generally only needs two levels of white light), I would say that neither is a great general-use kind of thing.
For "wow" factor, the M6 has that in bucketloads due to its relatively insane brightness [non-flashaholics will be impressed, I promise], and the Kroma has it in just how high-tech it feels. Neither are hugely pocketable (the Kroma in a jacket, maybe - the head seems too big for comfortable jeans pocket).
My absolute favourite light that I have consistently remained impressed by is my Milkyspit-modified "old-style" Surefire L1, with a good old UWAJ Luxeon-III. I just got a PD, too, and am enjoying that immensely.
For 250 bucks, I'd say there's a lot better options out there for a "user" light. For a "collector's item," the Kroma-Milspec is probably harder to get your hands on consistently.
Just my .02 Alaskan Dollars.