Maya is a 3D animation and rendering program, so you are unlikely to get usable vector objects out of it. You can export flat curves in some instances, but it really depends on the design and what you plan on doing with it in terms of modification. Importing into photoshop will at the very least let you move objects around, but I don't think it will handle textures or lighting nearly as well. Other than basic extrusions on text, I've yet to find a use for photoshop's 3d tools in relation to any sign projects. I have seen 3d vehicle wrap templates though and I'd like to give those a try at some point.