vivid red hair color - which brand is best?

Reds are the trickiest of all hair colors . . . they have not mastered the red pigment to the level of blonds and brunettes and they tend to fade quicker than their counterparts.
I have spent 10 years testing Reds ( as a colorist and a natural red head myself) in the search for the best and most vivid and luxurious red hair colors. Testing them on my self, on clients and in my mini lab . .

The very best reds are made by Wella in the their Koleston Perfect line of hair color. Wella make 6 different lines of hair color and only one I would recommend is the Koleston Perfect line. Its Wella's European line of professional hair color.  That can of course be bought online at different sources . . . if you really look  - -  you may Google: Killerstrands and we have a little underground store where you can purchase it if you have a hard time finding it.
The best for what you are talking about I feel would be 66/46 Forbidden - which is a LEVEL 6 Red-Violet in their INTENSIVE Reds collection...either that or 55/44 Passion - a level 5 Red-Red - this one is definetely comic book-esque . . . check out the color charts on Wella or over in Killerstrands Group.

hth
hope that helps