Board Thread:Questions and Answers Forum/@comment-71.190.189.13-20150309021246/@comment-24057866-20150309150341

For Vault of Glass, once you get to level 30, there really is no reason to do it on Normal. Doing it on Hard rewards you twice at all points--once for Normal and once for Hard--except the Gorgon chest. So as far as I know, whether you do Normal and then Hard or just Hard, you get the same chances.

Crota's End is a little different. Special and Heavy weapons only drop in Normal mode and Primary weapons only drop in Hard mode. Everything else is the same.