That's a funny coincidence:
I heard about iWhite Wizard for the first time today, had a call out from a woman this morning, she had dropped a small bowl of spag bol over her cream berber carpet.
She'd used this White Wizard on it, but it had not got rid of all the stains. As I had never heard of it before I said "Ooh, you may have set the stain, I'll come and have a look at the end of the day"
When I got there she had got most of it out but had blown a lot of the fibres in the process. All I did was put some Nemesis (original) on it, agitated it with a carpet brush, had a cup of coffee (which was kindly offered to me) then extracted with clean water, all marks gone, happy customer.
Although the White wizard didn't get rid of the stain completley, it didn't ruin the carpet like Vanish often does.
I think if she had persisted and agitated a bit lighter, she would have probably got the stains out herself.