Curlilocks is the expert here on Robert Craig but I wanted to chime in too because I have also used RC - I colored with RC for about a year and 1/2. On the plus side it is color deposit only, more gentle than other permanent colors and won't damage your hair as much. In my experience it works well if you want your hair to be quite dark. From the reviews I've read it seems to cover gray well for some people and not others. I ended up switching to a different permanent color because I couldn't cover the gray roots with the light auburn color I was aiming for and I didn't want to have very dark hair. I hope it works for you. Good luck!
Medium Texture/Normal Porosity
Conditioners: Curl Junkie conditioners, Elucence moisture balancing, Darcy's pumpkin seed, Mop Top Daily
Gels: CJ Pattern Pusha, CJ Curl Queen, UFDCM, Mop Top Curly Custard, KCCC (wish it didn't take so long to dry!), CJ Aloe Fix Lite
Weekly PT (CJ Repair Me) & DT
Icequeen method
CG since Aug. 08, still a lot to learn