Cavie was right... there was no discussion of which unit was right for me.
The one thing I was surprised at was the machine has a cell phone transmitter that sends stats to the med company and thus my insurance. You have to use the machine most all the time or they take it away from you.
The resp tech told me that consistent use will improve my wakefullness and other health benefits over time. I am going to miss those power naps hehe
Anyway, we take off for airport to fetch my new to me trike tonight at 3AM. #3 kiddo is taking us... cheers.