Hi,
I posed this question on the bacteria starter experiment thread.
I have used this product to set up my last 5 tanks. I did all of them as a fish in cycle. I didn't have any ammonia spikes and didn't suffer any fish loss or have illness either. I used the product at the recommended dosage for about 10 days. I also did large weekly water changes of 50%. I have always had many plants in my tanks as well.
I tested the water for ammonia and nitrite every few days and it stayed at 0.
I have always added about 10-20% of my ideal stocking right at the beginning of the set up. Then I add more fish after about 4 weeks.
All tanks have had different filters but I really cram the bio media in there.
This is just what has worked for me.
EDIT to add: whether it was the product that worked or my weekly regiment combined with the plants and careful stocking, I have no idea.