Pretty much polar opposites. Bright, neutral open back vs warm and bassy closed. They more complement each other than compete.
I don't have nor have I heard either. However I do have the HD 600s that the SHP9500s are often compared to. And I have both the Mahogany and Ebony variants of the Massdrop x Fostex TH-X00 which are warm, bassy and closed like the Sony.
For comfort the open backed cans with velour pads all day. The Sony's are probably more comfortable than my Fostex but leather pads make my ears sweat after a few hours. Less if it's hot. I never have a problem with any of my Sennheisers doing that.
Open back will obviously leak sound.
For fun listening warm and bassy is hard to beat. BUT If I could only keep one pair that I own now it would be the HD 600s.
But that's just my opinion and audio is completely subjective.
I've been watching those Sonys. This is the second or third time they've gone on sale this year. I don't think they do anything my Fostex doesn't do better though so I'd probably never use them.