Please read up on henna. There is a lot of great information posted on this forum about the benefits and application process. I don't have any problems with removal. If you purchase a BAQ henna you should be fine. I just mix with green or black tea, honey and oil either grapeseed or safflower. It washes out easily.I use Giovanni conditioners to co-wash after running water through until it runs clean. Hope that helps.
Oh the benefits are the color for my grays, conditioning, and thickens my fine strands. That along with the mud wash has my hair beautiful. To me anyway.