I picked up a EVGA GTX 670 to replace my GTX 660 oem 1.5GB and it came with Metro Last Light. I must say after my problem was fixed where I could not play at a higher res than 1440x480 because the game had a bug where if you were using your HDTV as your monitor, the Res field would be blank and crash if you tried to change it. 4A games released a patch and I must say this game looks amazing and runs great for me atleast.
Make sure you are not stuck in DX9 mode in game if you go to your video options and don't see tessellation then you are stuck in dx9 mode and the performance is 30-40% worse for me in dx 9 mode vs dx11. Dx11 I get 60-120 fps maxed out at 1920x1080 only ssaa is of where in dx9 mode I got only 30-60fps with the same settings, so make sure tessellation is in your video settings. If its not then delete yor Metro ll cfg file, that will reset your games settings and force dx11 mode.
Here is my Metro LL run with my EVGA GTX 670 OVERCLOCKED with everything cranked up except ssaa. http://youtu.be/E0NbPzIeBPU
If you are interested I have the unboxing of my Gtx 670 also on my channel. I will have the first hour up today or tomorrow.
Youtube - liquidg