Review (4/5): Make sure to bleach first!
If you are looking for a gift for someone who loves to dye their hair then this should be a strong consideration - the presentation is wonderful. Looking into the company, it's made in the USA, it's vegan, no animal testing, etc. and ammonia free (the smell doesn't bother me at all), fortunately. Make sure to rinse well afterwards.
The results looked great - very deep vibrant blues. I'm not sure it'd be an all-the-time purchase because of the higher price, but definitely works for a gift. So a strong 4/5.