I dont think its your uvs from maya. Its on your export from Zbrush. I usually 'fix' uv seams in Zbrush with a value of 10 to 14. Also in the export settings in Zbrush make sure 'group' is off. This can separate uvs when you export the model out for maya.

The low res in Zbrush always looks like that. The quality of your map output in Zb relies heavily on the subdivision levels of the mesh. More polys = better maps for output.

You do what ever you want with the uvs in Zbrush, AUV etc but if you export with that group on you'll end up with the same problem but with lots of little tiles.

If you are worried its your maya scene, check the normals are correct and make sure the uvs aren't split before making an obj

Jay