On my layout I used Atlas sectional tracks. The tracks needed rail joiner and feeders. I am not familiar with Unitrak, and I heard it does not need the joiners, feeders or ballast, am I right? What is the difference between the two brands other than the Unit rack is more expensive? Which one do you have on your layout? Are you happy with it?
Unitrack is much more rugged and can be put together, taken down, and put up again over and over. If you aren’t adding cork or some other ballast strip and ballast, the plain Unitrack looks better than plain Atlas snap track (I think). Unitrack is easier to put down … just one step.
Unitrack is good for a pure newbie since it can be assembled into any of the ‘out of the plan book’ layouts with little effort and less thought.
Flex track allows the more discerning modeler to introduce such prototypical refinements as spiral easements, ‘non-standard’ curve radii and proper superelevation. Then your track planning swings away from the Atlas (or Unitrack) plan book and toward John Armstrong.
It is not impossible to connect Unitrack end-to-end with flex, just a royal PITA.
Of course, I am biased. I am laying flex to radii not found in the Unitrak parts list, and building my own turnouts and specialwork (including multiple slip switches) from raw rail on loose (until I glue them down) ties. Eventually you will reach that point yourself, and your few remaining pieces of straight Unitrack will find a home in your display cases.
Model railroading is fun. Some of the fun is found in learning to make the difficult easy.
Atlas makes sectional track with roadbed much like the Kato track. Since you’re familiar with Atlas products already, wouldn’t hurt to take a look at their line too. Bachmann also makes a line of similar track/roadbed combination, and their line has many more items available than the Atlas and Kato lines put together.
You do still need to connect the tracks together, they do have rail joiners, and you do need to connect the track to some power to run trains !!