7S Cameron
1000+ Head-Fier
I have been using the HM5 pads in the office during the day (when it can be quite noisy) and the stock pads in the evening (when it's quiet).
HM5 do isolate better and add soundstage, but the audiophile in me prefers the stock pads' sound by a large margin.
I was the same way with the S400s and S500s. I tried a ton of pad-swapping, but always cam crawling back to the stock pads.