I've used it a lot and as long as it doesn't dry out it seems to work.
The inside of the chassis legs on my delta were caked with layers of wax (not waxoil) and the steel was rusting away underneath.
I use rustbuster Mil spec ASTM but can't vouch for it as it's hasn't been on long enough.
Built Hammer Dynamic S50, Nuxudol 700 and Donatol 1000 all have their followers but as I've no experience of them I can't comment.
Still have 15 litres of old Waxoyl from years ago and a few spray cans of the black Waxoyl spray and it is way better than the new version, We have used dinitrol cavity wax on a few things and it seems pretty good as we had to repair a dented box section on a restored old car and it was still rust free after 3 years of every day use.