I found this short but sweet Flex Seal review by on Amazon.com. The reviewer is Robert Privett an Amazon Verified Purchaser as well as a reviewer using his real name. If you have used amazon at all you know that they put some weight behind this.
Here is what Robert had to say!
“This product works as advertized. We were able to seal leaks in the roof of our garage from the inside. We haven’t tried painting over it yet. ”
As I said its a short one but I think he makes his point “As Advertized”. I wonder if he tried it on a boat?