I've had resperonics and now a resmed airsense 10. Personally I' like the resmed way more than the resperonic. It's much quiter, it's smaller, I sleep better with it, and it has way more control over setup. In addition to the setup the results from the sleep test dictate, I can set the humidity level, air temp, ramp time, and a bunch of other settings that I've fine tuned to help me sleep well.
BTW it works absolutely fine with my 12V batteries, either those in the trailer or my external battery pack. The 12v-24V dc-dc converter works on the external battery pack till it is down below 10V and will easily start when the battery pack is around 11.5V. Maybe they have changed the dc-dc converter design for the converter for the airsense.
Personally, I'd recomend going with the unit that best fits YOUR sleep apnea needs, then get the setup needed to run off 12V rather than pick a unit and then try to get it to work for your sleep apnea needs.
I trust the Dr and the sleep study technologist I went to and they said they never stick with one brand, there are enough differences between them that it's more of a "what is your apnea condition" and what unit maps best to your needs for a solution.
When I got my resmed, I was told to try it for 30 days, they would monitor the results daily and if not acceptable call me in for a different unit or brand, or if I didn't like it come in and the would try another type or brand.