I laid one on top the other, and really could not see. So this is the best picture I could take, with both headphones fully opened:

They at least seem to open up the same. But if you can picture it, in your head, the cups on the HP30 are directly over your ear canals. The cups on the HP50 have to extend so much further, and give me discomfort on my left because they never quite reach fully above or below, or give me enough depth on my left ear. I've read about some of the depth solutions, but there's nothing for the height or the discomfort when resting on the top of my head.
I'll really only be able to report more when I get back to work on Tuesday. National holiday weekend here - not enjoying it as much as my other headphones for music. So I'm not going to try to enjoy it here at home. I'll just use it at work, and see how long I can wear it, how much background noise it blocks out, and how it sounds with my daily dose of music.