I used Directions a couple of weeks ago - well, my hairdresser did, since I was too much of a wimp to bleach it myself, having heard all of the horror stories about what frequently goes. We mixed some 'lavender' with some 'plum', which resulted in Cadbury's purple, and I love it! Unfortunately, it runs a bit in the first few washes, so make sure you cover pillows, clothes, sofas etc. if you're going to let your hair drip-dry. I was also really scared of going out in the rain... It dyes your skin, too, if you don't use a barrier like Vaseline or (better still, I find) Body Shop Hemp Hand Protector around your hair line/on your ears - both when dyeing and through the first few washes. However, after about 3 washes, it's fine. It isn't quite as vivid as it was a fortnight ago, but still I think it'll last another 2 weeks or so before I feel desperate to have it re-dyed (and then the roots might need bleaching anyway). I wash my hair every night or every other night.
You should try it!