I have several D10's, a couple EX10's, a NDI, a D20, and an Extreme. All are nice quality lights, I love the fact they use 14500 cells (D10 and NDI) with no problems (or RCR123 3.7 volt cells in the EX10 and extreme). I would say they are on par with the Fenix lights for quality for the most part, though the switches on the Fenix lights do seem more robust than those found on the NDI or the Extreme if that makes any difference to you. On the Smart PD lights this is not an issue of course. I also love the variable brightness option on Nitecores, sometimes the Fenix pre-set levels are not exactly the levels you want, but the Nitecores can ramp up and down to any amount of light you want. Very nice lights indeed.