I’m currently using an Atlas Commander DCC system on my N scale layout. I chose it because as a beginner, I built my track plan based on one in an Atlas book (I believe it was this one), and I was very low on cash. 
I’ve been very happy with the system, but I do know it has some limitations. I’d love to switch to a Digitrax Zephyr system at some point, as I’ve heard nothing but stellar feedback on that one…but will I have to rewire my track or otherwise tear up my layout in order to do so?