I went back and forth on which one made me feel better and finally came to the conclusion that they both do their job very well. It was close but in the end I ended up choosing the ResMed. Here's some reasons why:
The main reason I chose the ResMed is because I found it's forced oscillation method less disruptive to my sleep than the single heavier pressure pulse
The Dreamstation uses.
Other reasons were:
1) the screen on the Dreamstation was too bright
2) the auto on feature didn't work as well on the Dreamstation
3) I preferred the look of the ResMed
The 2nd ResMed I tried, I kept. I was pleasantly surprised to see it had a feature the other one didn't have in the clinical menu: RESPONSE: standard/soft. I noticed my leaks and AHI were better using soft.
I did notice a couple other things when comparing Respronics vs ResMed:
1) The Respronics scores higher AHI's at the same setting than the ResMed does (even when using soft on the ResMed)
2) for some reason on the Dreamstation my inspiration 95% times were consistently way higher than my expiration times. I noticed Respronics in general seem that way in other people's sleepyhead screenshots too. Not sure if I'm just looking for that pattern and that's why I see it or if it even matters.
Anyways, I think that both machines did their job and treated my apneas very well and I felt great on both, I know I could have been happy with either.