I have used Captain Tolley's Creeping Crack Cure for many years on boats both sea going and inland.
Used correctly it never fails...
it dries clear, and the seal has a useful degree of flexibility, Its "capillary type" action allows the very thin fluid to penetrate where other sealers can't get to....
If folks have had problems with it then they are either doing it incorrectly or need to check that the seal required is one that can be reasonably be provided by the Creeping Crack Cure.
Usually a number of separate applications of the Cure are needed to deal with some situations.
I have no connections with the manufacturers, just a happy user of the product over many years.
As always,
Regards to all, and of course,
Happy caravanning
paws