Here are my two cents. Warning, this will be long but hopefully enLIGHTening. :twothumbs I've been at this whole flashlight thing for about a year so there are people with a lot of experience out there. I have been fortunate enough to become a reviewer for about 9 different manufacturers located in USA, Canada, and China. SO I have seen a good variety of features, build qualities, outputs, etc...
I'll just start off by saying I carried a Nitecore P12 for the longest out of anything. Currently though I carry a Surefire P2X Fury and occasionally carry a Surefire G2X Pro.
So there are obviously a lot of different aspects that go into the "perfect" flashlight. Thankfully you have narrowed it a little by saying tactical and belt carryable. I would say the next most important thing to know would be what is your use for a flashlight?
I live in Virginia so I'm surrounded by forest. My property extends for about 150 meters though so for me personally I don't need a light that can shine a mile. I need something that can reach the edge of my property if need be, but also something that won't blind me at close range in the forest or in my house. If you live in the middle of Nebraska where there are no trees and only farmland. obviously a thrower will be better suited for you.
For MY usage needs, I have found that the Nitecore P12 and the Surefire P2X are both absolutely perfect. I lean towards the Surefire though because:
1) it is USA made
2) I KNOW that it will last me because it's Surefire
3) it's very simple.
I used to think the P12 was better because it has so many different features. 4 different normal modes, 3 special modes, low battery indicator, voltage reader, etc... These features are AWESOME. But also IMO, the more features something has, the higher the chance of something breaking. The surefire has 2 modes. Low and High. No side switch or anything to add more complexity. I know that every time I click that tail switch, it will turn on. The low is perfect for anything close up and the high is great for reaching out at a distance. I also have a red filter for it if I don't want to be noticed or hurt my night adapted eyes.
SO out of all manufacturers' lights I've used (Fenix, Klarus, Nitecore, Surefire, Olight, Streamlight, Coleman, Bushnell, Maglite, and soon Sunwayman). I find that Surefire is the best built. Best feel and I have used their customer service, it is phenomenal.
BOTTOM LINE:
I would recommend the Surefire P2X Fury if you want durability and a life-lasting light backed by a US company with world class customer service.
I would recommend the Nitecore P12 if you want a ton of awesome features packed into a compact, easy to use package.