Hi Jack. I'm a strong proponent of Scaletrax and have used it extensively on a fairly large layout several years ago with great success. Their flex track is very easy to work with, very similar in flexibility to HO flex track. Their sectional track as you probably know jumps from 054 to 072 & 080 (or 081). It would be easy to use the flex to fill in any radii in between or greater.
Atlas, on the other hand has a greater selection of sectional track but their 'flex' is almost unworkable, especially for anything less than 080 or so! Atlas has the advantage of having a greater switch selection than Scaletrax but Ross switches can be used with either track system effectively.
Both are excellent choices for greater realism and it really comes down to your personal preference. I like Scaletrax as it has a lower over profile and helps my locomotives and equipment appear more massive by comparison. The middle 'blade' of Scaletrax greatly helps with this illusion by being much less visually intrusive than Atlas which to me appears too 'bulky' with it's much larger rails.
Tie spacing would have to go to Atlas however so it's really a toss-up!
