I had high hopes for it. I thought that all the 'it can't possibly work' postings weren't based on actual experience or knowledge, just mistrust.
Well, I used it to paint red over a white threshold which was already painted (years ago, not new paint).
It went on like primer- it stuck just fine but didn't cover/hide well. So it needs a second coat to fully hide.
So I don't see the advantage, I might as well use regular primer and then regular paint.