Are the Surefire "Nitrolon" lights the same as their metal brethren, exception being they are nylon?  Especially important is whether they use the same lamp/reflector assembly as the metal ones.

Do they provide the same performance as the aluminum ones?

SureFire's Nitrolon is a Polymer (aramid composite?) with Teflon in the mix. I have experience field-testing the G2, 8NX and recently, the new G2Z. I have also field-tested a number of Aluminium models such as the M2, M3T & M6, the C2 and I am currently field-testing a number of other Aluminium models.

First, I should point out that the G2/G2Z/G2R 8NX and 10X all have Nitrolon Bezels, but have Aluminium Reflectors. In the case of the G2x, it's the same P60 or P61 Lamp Assembly used in standard Aluminium models. The 8NX uses the same X80 Lamp Assembly as the 8AX, and the 10X has a Aluminium Reflector Assembly.
Models such as the M900 and P100 use Nitrolon in their construction but standard Shock Isolated Aluminium Bezels.

So what does Nitrolon have to offer the SureFire user compared to the Aluminium models?

Aside from Nitrolon's reduced cost compared to Aluminium. After all T8 Aluminium Alloy - ChemFilm'ed internal; Hard Anodised to Mil Spec Level III external; and in some cases, Nickel-plated contact surfaces is more costly.
For me cost is not an important consideration.
Performance is important, and Nitrolon has several significant performance characteristics.

1) Light-weight compared to Aluminium.
2) Impressive shock dampening properties against drop impacts etc. Nitrolon protects the Lamp Assembly better then non-shock isolated models.
3) Electrically non-conductive (HA also has better non-conductivity compared to 'standard' anodising.
4) Resistant to many chemicals.
5) Warm to the touch in the cold and wet.
6) The surface is such that it gives a secure grip without being tacky or abrasive.
7) SureFire offers the G2Z in standard matt-black, Olive Drab green, and for the G2, G2R & 8NX, Black, OD and bright yellow. Yellow is useful when you need to locate your SureFire in a hurry.

What the Nitrolon G2/G2R and 8NX don't currently have is LockOut TailCaps or Pyrex Len Bezels.

The just released G2Z Nitrolon CombatLight has a Pyrex Lens, LockOut TailCap, Adjustable CombatGrip, Lanyard and Anti-roll Bezel "Hex" style.
The G2Z is able to run the P61 High Output Lamp Assembly without you having to worry about the lens melting. This was an important consideration with the Lexan lenses of the G2 and 8NX.

Nitrolon can take a beating. In my field-testing of the G2Z, I was able to 'accidently' drop a G2Z about fifty (50) times onto tarmac. The Bezel rim had some dents and such. It wasn't until about the 50th accident that I managed to break the Pyrex Lens. I was surprised at how difficult this was to crack, but then I suppose it's 3 mm thick tempered Pyrex securely retained.
The great thing is that the P60 Lamp still works. It has slight distortion of the filament that has defocused the beam (making it less intense) but it's still pretty flawless - better then many other brands!

Do I have anything bad to say about Nitrolon?
The first thing is that it doesn't come in bright orange.
The second thing is that the G2 doesn't currently have a LockOut TailCap (LOTC) or Pyrex lens Bezel.
I have also found it gets hot when the SureFire is used constant-on for a while.

So from my experience, SureFire Nitrolon is very tough, resistant to physical and chemical abuse, shock dampening for the Lamp Assemblies, light-weight, offers a good grip and to top it off, it's cheaper then Aluminium.

Regards,

Al

That about covers it for the handhelds...

Were you refering to handhelds or pistol WeaponLights?