My plays with the camera told me what I needed to know. In poor lighting I can get a significantly cleaner, lower noise image of the same on screen brightness from the F3 than an EX3. I believe that the F3 with +9db gain still has less noise than an EX1! I'm really looking forward to shooting night time scenes with the F3.
I was shooting the Northern lights in Norway last week. I had a range of DSLR cameras. I could happily use the 5D MkII at 3200 iso while i had to keep the iso below 1600 on the 550D (T2i) to get an acceptable noise level (for timelapse video). Then couple that with a 24mm f1.4 on the 5D and a slower 16mm f2.8 on the 550D and you end up with a 4 stop difference between the two set ups for the same amount of noise, yet both cameras have the same iso ranges. To further add to the equation on long exposures the noise from the 550d increased more quickly than the 5D.