A Tung Oil Varnish like Formbys is what I use quite frequently.
I don't like Tru-oil and haven't used it for probably 30yrs. Never had good luck with it back then. Never cured/dried completely for me.
Others have great success with it.

The tung oil based varnishes are water proof,,or about as water proof as you can get. A straight linseed oil finish is 'classic', easy to repair and retouch/coat when ever you want. But it's as water proof as a sponge. Just the nature of the stuff.

With the right technique, and it isn't hard to do, you can get the same look with better protection using other materials. A lot less time involved too.

Most anything nearing a liquid form can be used to finish a piece of wood.
Some take longer to apply than others, repell moisture better, can be touched up better, dry quicker, take gloss better, build up on the wood as opposed to in the wood.
It all depends on what you want, are willing to wait for and sometimes what the gun you're working on demands for an original looking type finish.

There's no one single answer to which one is the best I don't think.