It's been a week since I got a CPAP machine. I've slept with it on every night since I got it, and I have to say: I've definitely noticed the difference. I'm less tired in the morning and during the day.
My family noticed it, too. More specifically, they've noticed the utter lack of snoring. It was quite loud before I had the CPAP. Now, just the quiet hum of the CPAP machine. I even used an old iPhone app called Sleep Analyzer to record any loud noises that occur when I sleep to prove it to myself. The loudest thing it recorded was me turning over in bed--a far cry from the snores it used to record.
Even better, of course, is my Apnea Hypopnea Index (AHI) number, i.e. the number of breathing events per hour that occur in the middle of the night that interrupt my sleep. Over the last 7 days I've averaged a 1.3, which is a definite improvement over what I had at my sleep study.
Another stat: I'm averaging about 7.5 hours of sleep a night over the last week. This is what my CPAP machine is telling me anyway but it gives a slightly higher number in terms of "therapy hours" which reflects when the machine is actually running.
My only issue at this point is traveling. At the very least this is one more thing I will have to carry with me on the airplane. I probably won't be able to use it on the plane for the really long trips but it's not like you can get really good sleep on an airplane anyway.