I have never used Quick Fix but it is probably the same as the product I use from urineflow.com. I buy a kit and it is more expensive than QF I think. I have been using substitution for 4 years and it has never failed me. Last time was 8/25/10. I am on a random drug testing program and am tested 1-3 times per month to keep my job. I go to Lab Corp. I am not observed. I have time during the day to use the heating pad because I find out by 5am and have until 3:30. So if anyone is in this situation that they have some time, I would recommend the urineflow kits but they take about 90-120 minutes to heat to the correct temp. I understand that QF is microwaveable. Hope you find this helpful. I was scared as hell the first time but after about 100 times substituting I am pretty calm. It has never failed me.