The original poster seemed to be concerned with realism in his track choice which rules out tinplate.
It's good to see more folks chiming in with favorable comments about ScaleTrax. When I was planning our layout about 4 years ago I was asking these same questions. Realism was my primary concern then and if I could build another layout I would go with it again without hesitation.
The limited choices in switches can be a factor with ScaleTrax but as Dave and Ted Hikel have shown, its not that difficult to use Ross templates and scratch-build your own switches using ScaleTrax rail and center from their flextrack.
Several of you have commentted that Atlas looks 'chunky' or similar - a good observation. The components may be close to 1:48 scale but consider that when working with scale models, more than just 'scale' comes into play. I read a great piece in a magazine talking about the differences between HO and O scales. The writer pointed out that an HO model of an F3 for instance is not 'half' the size of its O scale counterpart but actually 1/8 the size in volume. Yes, HO is technically 'half-O' but when you consider that the height is 1/2, the width is 1/2, and the length is 1/2 that you now have a model that is 1/8 the size in cubic displacement. This is why our O gauge pieces seem so much larger.
Now back to the track - when you create a 1:48th size model of an object the individual components may be true 1:48 but when combined together they can appear much larger. This is likely why the Atlas track seems crowded and heavy (which it certainly does!)
'Pros' like the Hikel brothers and Rich Battista have demonstrated the realistic appearance of ScaleTrax very well. Rich once posted several photos with the center rail removed in PhotoShop that looked as real as any prototype photo I've seen.
And it considerably less expensive than Atlas.
Gargraves suffers from the oversized appearance too. We have some 'G' Gauge two rail Gargraves that looks great with a large scale locomotive as it is about right for them. For 'realistic' appearance with O gauge trains it is just too big...