I've had my CPAP for about 2 years and it makes quite a bit of difference... when I use it.
I am REALLY bad about not using it for weeks at a time. Then I will get so run down that I can't do anything online and have to force myself to start wearing it again. It's not that is is uncomfortable or that I think I look funny when I wear it, it's just that I get lazy. I stop using it and pretty much within a couple days I start on a downward spiral. I fall asleep at the monitor, become grumpy, want to sleep more, have almost zero concentration.
Been about 2 weeks since I used it last. It's sitting right next to my bed, I don't know why I don't just slip it on at night.
Been working long hours the past couple weeks trying to get new stuff off the ground and I know much of the exhaustion I feel could be eliminated by wearing my mask. I think tonight I will be putting it back on. Hopefully I can stay on the CPAP wagon.
Here is the machine I use:
I've also been wanting to check into Provigil
http://www.provigil.com
It is supposed to make you much more awake during the day without making it hard for you to sleep at night.