Today I am trying velcro rollers for the first time, I threw them in very quickly (I'm supposed to painting the salon floor right now), and I quickly pincurled the back.
I would imagine a positive of using them would be the consistent shape of curl. I usually use foam rollers, which obviously don't maintain a shape, and often over time completely lose their shape! In theory they should lead to a 'nicer' curl. Another positive would be that the hair would dry faster, as air can more readily circulate, compared to a foam roller, which must retain a lot of the moisture. They would work well under a hood dryer for example.
The negative for me is that I usually sleep in rollers. This ensures the hair is bone dry before brushing out, and I like putting in rollers before I get into bed.
I have put a silk scarf over the rollers, and I'm good to go and paint that darn floor!
Have you used foam and velcro rollers? Do you have a preference?