Don't know why XTrakCAD wasn't one of the answers, but the price is right, the results seem right (won't know until I start laying track), and it lets me run sample trains to test operation, etc. I tried RTS, but found XTrakCAD when I hit the 50 track trial limit and never looked back. I have used a lot of paper though. I print what I think is the final design and see something I want to change. But, the ease of making those changes, trying different things, etc., are all easier with software than they were with the templates, pencils, erasers, etc., I used 30+ years ago.
It also wouldn't be near as easy to see the differences between (N-Scale) E-Z Track, Atlas, and UniTrack. I'm amazed at how much brand selection affects what kind of a layout you can design. I'm dealing with a lot of limitations due to size/space (10x6 tabletop with detached 6x2 staging yard), so I appreciate being able to "see" how different the design will have to be if I change from E-Z Track to Altas or UniTrack. For example, I can't come close to the staging area design I have now in E-Z Track when I try using Atlas track, mostly because of the difference in the switches.
I haven't tried the UniTrack parameter yet, but my goal is to use flextrack for the straights without having to deal with the differences between ballasted E-Z Track and plain flextrack. I can't seem to find switches comparable to the E-Z Track specs and that completely changes the dynamics of crossovers, spurs, etc., most noticeable in the staging area where there are a lot of switches.
EDIT: I think I figured the switches out and was able to add to my design using the Atlas parameter, so I'll see where that takes me.