Polyurethane - is widely revered as one of the most durable yet easy-to-apply protective wood finishes. Polyurethanes are now available in both oil-based and water-based, and there are differences in the way in which both are applied and in durability. However, for many projects that will see a lot of wear and tear, few finishes are as appropriate as applying polyurethane for the final touch.
Lacquers - Most professionals still regard lacquer as the best all-around finish for wood because it dries fast, imparts an incredible depth and richness to the wood, exhibits moderate to excellent durability (depending on the type used) and rubs out well. There are several different types of lacquer, and they exhibit different performance characteristics.
Acrylic - Water-based finish contains some of the same ingredients as varnish and lacquer -- notably urethane, alkyd and acrylic -- but many flammable and polluting ingredients have been replaced with water. This durable, non yellowing, wood finish is formulated for interior use. This fast drying, low-odor finish beautifies and protects interior wood, may be used on displays, crafts, decorative painting, watercolors, charcoal, pencil and other painted surfaces.
It just depend on the project what you would want to use as a finish. I use Poly on furniture or where a more durable finish is needed. Most of my scroll saw projects I use either lacquer or clear acrylic spray.
