When comparing the red removers from leading manufacturer's, I suspect most of the variation in performance is due to the stain or the carpet fiber or the presence or lack of protector rather than how good a product works.
The best red remover is going to be fresh. Reducers do have a limited shelf life and time in a hot van during June or July does nothing to help that. Whatever product you use, keep a fresh bottle around.
When we developed RedZone Ready, we did a lot of testing against Red Relief which was the #1 seller at that time. 50 pairs of identical red stains on white carpet. Half cleaned with RedZone Ready. The other half cleaned with Red Relief. then a panel who did not know which product was sued judged the results. 42 of the stains were totally removed. No one found any difference. 3 of the stains, the judges picked Red Relief. 5 of the stains they judged that Red Zone Ready did the better job. Officially -We Won! Yea!
In the field, you will probably have similar results with any good product if you follow the directions and if you use fresh product. If it doesn't work, blame the lack of protector on the carpet. Don't blame the stain remover.