Yes they work good but its a seasonal application. The stuff is harmless to rubber and plastics and does not stain.
It is environmentally friendly also which i like better than petroleum based products.
No point in damaging the Earth unnecessarily right.
Hit the whole underside of the car every autumn liberally with these products and it will be fine even in the salt belt. great if you don't mind the yearly investment.
If the question were phrased, "are they as good as traditional rustproofing"? the answer is yes but only short term.
These are perfect also if you have an old car that only sees summer use but you still don't want rust to get a start.
They are not a spray and forget product. Here is some info..http://www.cortecvci.com/Publications/Reports/reports.phphttp://www.cortecvci.com/Publications/Reports/powerboat-article/Powerboat.pdf