I had both, previous model with deep throwy reflector and the newest with shalow reflector and writings around the LED. ....So from my observations:
The new V4 is not as throwy as previous revision, but it is still a good thrower. Throw is equal to my EagleTac M2XC4 Neutral (which is around 23K lux), but with bigger hotspot. The spill is much wider and donut hole is almost invisible. The light is more powerfull too (more current to the LED). So from "raw power" point of view it's a very good light.
Unfortunatelly, reflector is not the only change. The body tube is different and the head is assembled from two parts. One for reflector and lens and one for LED and circuit board. The two parts are screwed together (no glue). With that power level, the flashlight "should" warm up very quickly (it's light, there's not much aluminium heatsinking mass) but it's not. The LED has poor thermal transfer to the pill and the pill to the body. This means the LED is very, very hot and I'm affraid about reliability in long term use. Apart from this new M1X, I have also EagleTac M2XC4, Fenix TK45 and one custom MC-E flashlight ...and I know how fast the body of powerful flashlight should warm up. Also the clicky switch is not as good as previous one. It feels just worse... The lens is worse too. The previous one had a nice blue-violet coating. The new lens looks just plain normal (however, I may be wrong with the coatings and lens quality). Overall, the new V4 is showing "saving costs" in almost every aspect. Yes, it's powerful and the beam has a nice shape and it still throws very well, but I'm very affraid about long term reliability because of this poor heatsinking and lower quality switch...
Stick with your V3 ...it's better product in my opinion.