The name of this finish often is used generically for a finish or top coat. It's very durable because it contains a higher ratio of solids. Spar varnish is perfect for outdoor projects and for raw wood used for exterior doors and trim on rustic homes. In addition to protecting the wood, it also provides natural ultraviolet light protection. Spar varnish is often used on items that will be near or on the water, like a wood boat, decks, beach chairs, etc. Apply using a natural-bristle brush.
Lacquer provides the extremely intense gloss finish often used on many Asian-inspired or ultramodern furnishings. It is extremely durable and resistant to damage; however, over time it can begin to discolor and become scratched. Wonder why it's so smooth? It's applied via a sprayer, because it is more viscous (thinner) than the other finishes. You'll need a high-volume, low-presser (HVLP) sprayer and a well-ventilated and spacious workspace to apply it.
Cutting boards and other wood items that come in contact with food do well with butcher-block oil and food-grade mineral oil. Wooden tool handles will hold up better with an annual rubdown with boiled linseed oil.