I have Deks Olje 1 on our dinghy it has been there with more or less annual quick once over refreshers since 2000 good stuff, no wood rot and still looks fine.
I have used le Tonkinois on cockpit locker doors and patchily on the mast, it's expensive and I have only found two UK suppliers, but easy to use and organic. Jason tried it out for LBBY but said it lifted on their sample.
Our mast which now needs fully stripping is originally Coelan and this would seem to have lasted a good 10 years. It's like a plastic film on the wood, really, once you have covered the required number of coats; and costs a vast amount of money, but is very high performing.
Once I have used the last of my current stocks of good varnish, stored indoors for frost protection, I am off to B&Q for their marine varnish, which was very effective on Rondonay when we had her.