Deirdre asks:

Which roller systems work best (least painful to sleep in, best air-drying time, best well-formed curls, least need for products for decent results) on natural hair?

CN’s Response: I’ve got everything from old school foam rollers, to flexis, perm rods, magnetics, and even Curlformers. I rocked perm rods and magnetic rollers for a year– they provide very firm sets, and quick drying times.
I’m not a fan of the sponge roller, but the satin covered ones (purchased at Walmart) work great on my dry Braid-n-Curl and Twist sets. I’d never use these rollers without the satin covers (drying), and I’d probably never try them with a wet set either (poor drying and the product may be absorbed).
Right now, whenever it’s Twist-n-Curl time, I turn to flex rods. They are foamy and contain no hard or sharp clasps or securing mechanisms– I feel that they result in less stress to my delicate ends. The only draw back is that my hair seems to take longer to dry.
For me, no roller is comfy to sleep in, but the flexis (with only the last 2-3 inches of hair rolled) are easy to toss over the top of my pillow so that I don’t have to lay on them.
No matter the type of roller, I usually opt for the smallest size to match my wave/curl pattern.