You are also able to export out the map and check it in Maya. If the seams are off simply go back into ZBrush and use Zapplink to use the photoshop healing brush to fix seams "extremely easy." You also now have the ability to paint directly on a 3d object in Photoshop. Is up to you but I prefer the Zapplink method.

Are you using the original obj or exporting a new one out of ZBrush?