I only use white printable. I suspect the only difference between white and silver is one gives your printing a white background and the other a silver one
I have only used one brand of white printable DVDs but I think some may be more absorbant than others. I say that because the Epson printer I use warns that it can take up to 24 hours for the ink to dry! Its the same ink it uses for printing on paper, of course, so the only reason I could see for long dry times is that some DVDs don't let the ink soak into them like paper will to speed up the drying. BTW, the printable DVDs I use seem to dry as fast as regular paper.