It's perfectly fine
I have naturally blonde hair that I've been dying dark for YEARS.  My eyebrows look nonexistent if I don't fill them in. I usually just use the color I use for my hair and tint my brows that way, but I wanted to try something new. I do love the small, individual sizes this comes with, as well as the little mixing cup and brush and stuff.  The first time I used this, I only left it on for about 5-7 minutes (after reading some reviews). It didn't get as dark as I wanted and didn't last long. The second time I left it in longer, maybe 15-20 minutes. It definitely got darker and has seemed to last longer. The next time I do it, I'm going to leave it for half an hour and see if that makes a difference. I don't have any input on staining- I'm very careful with the application and haven't had any problems.  If anything, this will be nice to use as touch ups between dye jobs, haha.
Rating: 4 stars