As far as rust-prevention goes, I would caution being very sceptical about the results of published comparative tests. Every one I've seen done by a commercial publication, without a single exception, would fall short of a proper scientific comparison. Some even acknowledge this in the text!
So they are far from definitive and the wildly differing results for the same products should throw up warning flags. In one test WD-40 did very well indeed, despite its known weakness as a long-term rust preventative. In another BoeShield did poorly — for one reason or another — when it is widely acknowledged by professional users to be one of the best products there is (not an endorsement of BoeShield by the way).
If we go back to the era before modern scientific coatings and see what they recommended it was oiling or greasing (e.g. with tallow) or waxing. All of those are still viable ways to go for rust prevention. From user experience they all work when upkeep is maintained.
But for rust prevention and surface glide IME there's a clear winner: wax.
If you leave enough oil or grease on the surface that it's as slippy as a well-buffed wax coating it'll be actually greasy, which is all sorts of bad. Apart from the obvious risk of getting wood greasy from direct contact, your fingertips can get oily and transfer this then to the next piece of wood you handle. And to top it off, with that amount of oil on the surface dusts of all levels will cling to it.
So wax it is. Paste wax specifically. Before you run out to buy any it's incredibly easy to make at home, cheap too. All that's required is wax to be melted with spirits or turpentine (or dissolved in the solvent in a warm spot like a sunny windowsill), poured into a suitable container and left to set. That's paste wax, indistinguishable from many commercial varieties except for colour, and possibly smell.
Waxes to try:
- Paraffin wax (as in most white dinner candles, in North America canning wax is another source). Usually far and away the cheapest option.
- Beeswax. slightly tougher but more expensive.
- Carnauba wax, which is very hard. Not to be used by itself, but as an additive to make the dried wax coating harder.
So for the cheapest coating with good wear resistance use paraffin wax mixed with a little carnauba.