Actually, the stuff I bought was more expensive than GE Silicone II. It was the most expensive stuff HD had. The tubing is cardboard and cheap which to me is a good thing on an expensive product; less on packaging, more on contents.
You think Polyurethane will be good and last? Like I said, I prefer them to silicone for this application, you ever used them?
PL Sealants & Adhesives