I have a TK40 for about a year already and it's not the brightest LED light anymore. I have to say that light served me alright over times I have used it. The "WH" tint cool white is just plain bad for me as I switched back to incandescent. Also with 75 CRI everything just kind of merge together.
Well it's $150 bucks that I would spend on the new TK 45 with triple XPG. I also feels that the HA coating on the TK isn't as well as the Surefire. There are actually pieces coming off with normal use. Normal use for me is putting it on the seat of the car and in my pockets. Plus the knurling on the TK40 aren't as good as my Surefire lights. The knurling on the TK40 is like as if it weren't there. About the window on the TK 40, it's clear but not coated as advertised. It probably water white glass as it's quite clear comparing to soda lime glass. Also the switch actually pisses me off as it's a reverse clicky. The UI of the light requires you to click like 5 times to change to get to a setting. One thing about the emitter is that you don't know what flux bin you are getting! You could get a better one without knowing so it's a lottery there. This means that one light could be brighter then the next one you can buy. Did I mentioned the emitter is a cool white emitter? For a $150 light I will say it got some good features. The light does uses AA cells for power and it's water proof. Actually that's about it for what's good.
Ok, if you need to stick to AA cells and have $150 I think there are better options out there. I personally will get the Surefire E2L AA Outdoorsman 2 modes. The thing about the outdoorsman it's not really 80 lumens output. It probably does actually 100+ out put and it's small enough to pocket at all time. What good does a light do if it's not there when you need it? Also check out the warranty of both company. As surefire have a unlimited replacement on damaged parts, while Fenix have a limited one which you pays for part but not the labor. The E2L AA have a forward clicky, simple 2 mode low/high UI, TIR optic(no reflector lumen loss which could be up to 30%), you break it Surefire replace it warranty, and it's a small light with a clip for EDC.
Ok if you need power and AA cells as requirement, I think you are best stick with Mag Hotwires. As it's still power by AA cells, but with high out put(could be 1000 out the front lumen) and can be made pretty cheap. 100 CRI rating is something that a person can like pretty fast. As you can see more colors and the shapes of the objects you are illuminating. Cool white LEDs can't give you as much colors but you can only see the shapes. One big plus is that you can set things on fire to impress you friends and family.
The drawback is you need to get the parts and less usable run time.
So if you are ok with Li-ions. You don't need the TK40 as it's big and uses an outdated cell chemistry and emitter. The high CRI Ra-Clicky looks like a very nice light for the money. It's the only stock light that I know that uses a SSC P4 93CRI emitter. Surefire C2, 6P and others are good with D26 modules. The options are like candies in a candy store. Also the new EagleTac lights are very good too, as they now have drop in models. This means you can use 18650 secondaries and the ability to upgrade if you want.
Anyway I hope that you can find the dream light that you seek like everyone else here. To me the TK40 is not a good light for the money, as there are much much more better options out there for the same price. Cree MC-E is an outdated piece of technology, as the efficacy is pretty bad comparing to the XPG. To me people who could really use the TK40 are people who needs longish run time, and brightness. The price for the two things are 75CRI, high price,AA cells and the size of the light.
Happy hunting.lovecpf
