I am currently using the AirSense 10 for Her machine and in the special for Her mode. I got it mainly because I was curious to see that mode in action. It works well for my needs but I have also seen a couple of people who that mode didn't work so great and we couldn't ever really figure out why. It just wouldn't respond like it should sometimes and other times it worked great.
Don't let this scare you off if you are thinking your settings exceed 12 cm. It's not like the machine won't go higher...it will. I have seen it happen on my own reports because sometimes I need 16 to 18 cm. You just need to be having something else going along with an OA like flow limitations or snores for it go higher than 12.
Treats apneas up to 12 cm H2O and continues to respond to flow limitation and snore up to 20 cm H2O.
Is it absolutely critical that someone uses this mode over the regular mode (which is also included in the for Her machine)????
I don't know the answer to that one. It's a maybe. The changes are less abrupt and for some people (male or female) the softer changes might let a person sleep better. I was never one of those people so I can't say if softer is better. I have used an ASV machine which has the most abrupt changes available and slept well right through them. So can't use me as an example that softer is all that important but it can be for some people. Is this something only a woman might appreciate....I don't think it is gender specific myself and I think that ResMed probably shot themselves in the foot a bit targeting women. What that other for her mode does could just as easily be potentially helpful for the male of the species but ResMed decided to target women.
Using cpap can sometimes not be so easy and if a different mode is available to try....and someone is having trouble adjusting and sleeping well then to my way of thinking the more weapons we have in the arsenal to fight with the better our chances of achieving success. That 3rd special mode is just another weapon in the arsenal. Better to have it and not need it than need it and not have it. You don't have to use it if you want want to or need to but how do you know until you try something. Is it critical for most people? Probably not but what if a person is the 1 out of 25 (or whatever number) that might actually do better with that mode?
The biggest difference I have seen is when the machine decides to adjust the minimum higher when I have 2 OAs within the time frame. Sometimes I see it happen and sometimes there's no need. If it didn't do this for me in the middle of the night I might end up with an AHI where I would be needing to use a slightly higher minimum all night instead of part of the night.
Would this be the end of the world...of course not. I have done it for years with the other machines but I kinda like not having to use higher at the beginning of the night. I can do higher but lower is just easier and more comfortable for me.
I am always about easier and more comfort.

Why use higher if I don't have to.
I may have to RISE but I refuse to SHINE.