I've been using the ResMed AirMini pretty much continous since it's my only working CPAP and I'm waiting for a replacement for both the Dreamstation and the Dreamstation Go. I will probably stay with the AirMini since it's smaller and I really like it. I'm sure there probably is some noise level but honestly I don't hear it. I put the mask on and push the button to start it and I don't hear it start but feel the air that starts moving into the mask and that's how I can tell it's on. I don't use any humidification system. I stopped using it when I had the Dreamstation Go as it seemed to make it harder for me to breathe. I have to say that my bedroom is in the lower level of a walkout basement type house and I have a whole home dehumidifier that keeps the humidity around 50% even in the Winter.

You can buy the battery packs that let you use them without an A/C cord but I don't go camping anymore so it's a moot point for me. I suppose it would be worth it if the rolling brown outs start 🙂 I think most of the portable batteries supply 1 to 2 nights of CPAP usage before you have to charge the battery.