I have to bring some kind of playback device, but a controller/laptop is expensive, prone to failure (playa dust kills electronics about 4 months later) and very heavy. I’ll be walking all over the place, so a wallet of CDs + a couple of USB sticks is about as much as I can reasonably carry. I will be sealing them in a ziplock bag when not in use 🙂
My concern with MP3 CDs is that old CDJs don’t support them. Also, I use WAV normally, and a WAV CD holds no more audio than a standard Redbook/Audio CD.