Personally, I'd go with ScaleTrax and bend my own curves.
ScaleTrax has smaller rails in a true rail shape amd nice scale ties. Some say the tie spacing is wide but they look good to me. The middle rail is also black and very thin, it dissapears easily.
The Flex sections of ScaleTrax bends easier than any other I've heard of.
I have some and you can literally nail down the end and move it to where you want it to screw it down with just your finger pushing it. I have bent it down to about O-22 with no trouble (Just as a test). It even straightened back out easily (minimal residual curve).
Check out www.toytrainsontracks.com
They sell a couple videos on Layout construction using that track.
Previews of the videos show the track well.
(And NO, I'm not associated with them, other than owning a set of the videos)