If you want Surefire durability at Nitecore prices, what about Solarforce? Specifically, their various Surefire clones. I have not tried those yet, but I have a Solarforce Z2 and it's OK; the quality is nothing to write home about, but it's not terrible either. It's a nice little light, especially for the price.
The difference with Surefire - and I am referring mainly to the 6P, as I have one of those - is the way it is engineered. It reminds me of Soviet-era Russian military engineering, in that such hardware was engineered to withstand both the need for field servicing, and the possibility that it might be poorly made at the factory. The 6P has a very simple construction, so it's nearly impossible for anything to go wrong. Yet it has some clever engineering like the double spring on the P60 module, which ensures a consistent electrical contact (crucially, in both directions) under all sorts of conditions, even if the parts do not fit together very well. Most similarly-designed lights have zero or one springs at the business end, which makes them a lot more sensitive to damage or manufacturing variance.
I plan on building a clicky 6P clone at some point out of the range of Solarforce lego components - possibly using one of the many other P60 modules that are available; not necessarily a Solarforce one. Given the way the 6P (and the P60 module especially) is designed, there really is very little that can go wrong even if it is badly made, especially if you go with the Surefire-style tail cap rather than a clicky. Although from what I have read, the Solarforce ones are constructed as well as genuine Surefires anyway. If it comes to it, the modular design at least means that parts can easily be repaired, replaced, or upgraded as needed.
I also happen to have a Nitecore P12, and while it isn't terribly badly made, the attention to detail and finishing are certainly among the worst for the Chinese lights I have (and I have at least one from all the main brands). I can easily believe that the electronics are neither reliable, nor easily serviceable. It's probably the light I've found most disappointing compared to the "on paper" specs that made me buy it, although I doubt very much that I'd have found the equivalent Fenix models (such as the PD35) to be any better.
The downside of a 6P style light of course is the slightly larger diameter around the head, but it's not a huge difference. I find both too big for EDC anyway, so I have an Eagletac D20A Ti Clicky for that purpose. The P12 and the 6P are both about equally pocketable for those occasions where I need a slightly more substantial light. In that regard the P12 is certainly bright (and can be quite efficient in low-power modes), but it's not very throwy, so outdoors it often doesn't seem as bright as it really is. It has one of the more effective "tactical strobe" modes if that matters, but the efficacy of strobe for self defence purposes is dubious at best.
Of course, if the OP's question was "are Nitcecore so badly made that I shouldn't buy one even though the size, specification and price are exactly what I want" then the answer is no, just buy one, it's as good as anything you'll get at that price. If the question was "can Nitecore be reasonably described as durable" then the answer is also no. However the same is true for most things: if you're not going to be in a situation where your life depends on it, you're better off buying something cheap and OK, then replacing it when it fails rather than spending 2-5 times as much on a brand like Surefire that has a much higher standard of quality control. If OTOH, you expect to be dropping it a lot and durability is one of your main considerations over size, UI, etc., but it's not exactly life-critical, then a 6P clone is probably the way to go.
Also, if you are going to be in any situation, life critical or not, where you really depend on your light, you should have at least one backup, since the most reliable can still fail for all kinds of reasons, including the battery running out unexpectedly. One nice thing I will say about the P12 is that I have found the low battery indicator to be pretty reliable, whereas most LED lights I have when running on LiIon will simply cut out when the voltage gets too low, but since they are regulated you get no warning that this is about to happen (the light level stays exactly the same until it suddenly cuts off).