Seems like you are "Hooked on Nitecore" ?
Fenix changed the style of their lights after getting sued by Surefire for their lockout feature. I got hooked on their lights around 2007 when the P2D, P3D, L1D, L2D, L1T, L2T, and TK11 came out. I liked the interchangeably of most of those lights' bodies and tailcaps that allowed for adaptability for long trips and easier replacement if batteries leaked or the light was sawn in half. Also liked the durability of TK series lights and ability to use 18650s when 123As cost a fortune. That company got me hooked on flashlights, hence the name. New Fenix lights have mostly abandoned an actual low setting and only give about 25-30 lumens low for lights with larger cells making them less useful for emergencies. Foursevens Quark Pro lights picked up the slack in that area for awhile so I got a Quark Pro 2A. Then they went out of business. The new company changed the light to where it wasn't the same.
Nitecore for several years has come up with very good products pushing the limits of how small, lightweight, and bright a flashlight can be. Durability is also important to me. I used an HC60 headlight for work and I could not break it after dropping it off from above an 8 foot ladder (probably 10 feet). A Jetbeam headlight it replaced didn't survive the same test. Headlights slip off of hard hats all the time. Nitecore is even making their own purpose built high efficiency l.e.d.s now. They don't just pay attention to the brightness, give best runtimes on low, or make the smallest powerhouse you can pack in the least amount of space, but they add features like voltage testers, digital displays, magnetic bases for hands free options, and products for emergencies like a electronic strobe/whistle and a lantern/USB charger/21700 battery kit.
Edit: I still use my old Fenix lights. Have to have something on me to hand to someone for a loaner that I don't need to provide a user manual to tell them how to turn the light on. Fenix PD30 R4 with a 16650 and Fenix E01 v.2 are part of my edc, but if limited to 5 lights they just didn't make the cut.
