Microneedling is far superior to dermarolling. Reasoning behind that fact is due to the wound created. Dermarolling creates "V" shaped wounds. Picture the needle rolling over the scalp... it doesn't just go in straight up and down, it rolls into it, which causes the excess damage. Microneedling does go straight up and down, so it makes cleaner "I" shaped wounds. It heals much faster. You can also go deeper and have less damage since you aren't making a huge wound.
Being able to adjust on the fly is nice as well. Some parts of your scalp are thicker and require more depth, other spots are thinner and need less. I use .62mm towards front, 1.5mm near crown.
Dermastamping would be a better option than dermarolling if you don't want a microneedling device.
I started with a dermaroller and swapped to a microneedling device after about 2 months. I use a Dr. Pen A6 ultima. Bought it on Ebay for around $60.
I use 12 needles because when I was researching it the people with the best results used 12. I'm not sure if more needles would really change anything.. but I know when dermarolling, more needles was significantly worse for me.
