For decades, Märklin offered the only complete track system for Z-Scale, but in 2005, Micro-Trains began its introduction of another line of Z track to complement its line of Z-Scale locomotives and rolling stock. Called Micro-Track®, this line of track incorporates a roadbed with the basic track to create a realistic looking layout. The product line has progressively expanded from a basic oval to add turnouts and other track pieces. At this writing, a second radius of track has been announced and it is anticipated that further expansion of this line will continue.
Micro-Track has the same track geometry as the Märklin track, and it is my understanding that the two track products can be used with each other.