They worked fine in my 6S and the #4 plate. Remember, YMMV.I have a tough beard and sensitive skin. BIC Chrome Platinum blades are some of my favorites. They are super sharp, so they slice through my beard, but they are smooth enough to be used without irritating my skin. Of course, for many people, they are going to be too sharp to use in an aggressive razor.
I question the comment by @albsat about the BICs not working in a Rockwell 6S. Since the razor comes with six plates allowing the razor to be adjusted, I would have thought at least one of the plates would have worked with BICs. If he only tried one of the more aggressive plates, then I can understand the blade not working.
One thing I will say about BIC blades is that they will let you know very quickly if your shaving technique is deficient. You need a good lather and a good technique.