I have only used it for the last eight months or so, however, it does seem ok.
My limited experieance;
It won't stop the rot if there, but after the bike has been stripped, cleaned, and put back with all the love it deserves, it will hinder it.
A damm good clean, then leave a good film of it on, that's a big point of any protection, and ignore those around you that "polish it off!". A gentle wash months later, and
Unless laying the bike up, putting it on anything that will get hot is probably a waste.
If you want to spray it, make sure you don't put any where your hands, feet, rear end etc. contact! Ride around with your brakes on for a few miles... I've known "professional" drivers put cockpitshine on their aiming wheels...
Not as messy as taking vasaline off brass, but you'll appreciate the saving none the less.