In which I sing the praises of the AZ2
This is one of my favorite mid-size lights. Here's some of the reasons why.
I have a big soft spot for floody area lighting, and the AZ2 delivers this in spades; it rivals the Zebralight H501 and H50 for a nice wall of light without using a diffuser or frosted lens setup. Unlike the ZLs, it also has decent throw, at least on high mode, making it a very versatile light. I also have a strong preference for neutral and warm tints. the AZ2 is a cool white light, but it's warmer than most CWs, and only looks cool when going head to head against a NW tint. The 5mm LEDs have no purple or blue tint like that breed normally does

; outside of some warm 5mms used by a few custom makers here, they're the best tint I've ever seen in that style. Makes the light much nicer to use than a white A2L or stock white A2 on low. The K2's got a nice warmer side of cool tint too. There have been enough reports from other people with this light about the tints that it doesn't look like a case of me winning the tint lottery. It looks more like a deliberate decision by Surefire. Now if only they'd pick premium tints for their other LEDs too (I've been lucky with the tints of my XR-E SFs, but I've seen some that are sickly greenish, and all the P4 lights I've seen have been way too blue.)
I have to admit to nostalgic fondness for the K2. I'm not sure why it didn't seem to catch on with flashlight manufacturers when it was current a few years back; I've had a couple of lights with them and never had a bad tint, and think it makes for a nicer beam than the XR-E in a non-throw oriented light.
Too big for an EDC, but it carries well in a jacket pocket, waiting for when I want a bigger light than the small ones I usually carry in my pants pocket. Very comfortable to hold, and I love the genius simplicity of the two stage tailcap. Great for momentary use, or constant on low with occasional flashes of high.
There is a downside; I wish that the runtime was a bit better, though the output levels are fine for my uses -- makes a good light for night time walks; the 35 lumen low is more than enough for lighting up the sidewalk or trail, and high works great for annoying the neighborhood dogs who bark as I walk by. I'd like to see more knurling or texturing on the tailcap to make it easier to twist one-handed. Then there's the usual SF complaint about not supporting rechargeable batteries. And, finally, I wish it came in a green or grey HA finish instead of black. Nothing I can't live with, though.