Review (5/5): The brightest blue!
Manic Panics colors are SO vibrant but, yes, as with ALL haircolors that are any more complex than spraying a pressurized can at your head until you look like a colorful Ken doll, you just must use a lightener on your hair to get the full color effect. No color brand has quite broken the physics that is the color spectrum, so any dark hair color will cause a darker than ideal tint.
Bottom line:
When used as recommended (i.e. on lightened hair) Manic Panic gives the most breathtaking hues, and without any animal products or testing (i.e. no bug dyes!), it is super easy to apply (it foams so you don't have to guess if you got every strand!), doesn't damage your hair (that's the bleaches job!), and lasts a decent time.