I have tried it. It works and it is real. It is good. Not a hack either.
The creator of it developed it for lock on (which is why the download says, 'Lock On HDR'), but it does indeed work with no discernble performance hit in Il-2. It really needs converting to OpenGL though so we can use it with shaders=1 and Perfect settings. Hauntingly beautiful. The look of it gets imprinted on your retina.
The fellow who made it has not worked in GL for years. He says a conversion would be possible, but he is not an Il-2 player and will not be taking the job on.
Someone who has FSX should give it a go too!