If you're going to buy just one tool for pruning, make it a pair of handheld pruning shears.
This is the tool you'll use for pruning roses and for most cuts on fruit plants, houseplants, and young ornamental trees and bushes.
Better quality pruning shears cost more and are well worth the extra money. But 'better quality' can mean many things: a tool made from better materials; a tool designed to cut better under some circumstances; perhaps a tool that is more comfortable to use. This last point - comfortable to use - is most important.
The business end
The business ends of pruning shears have either anvil or bypass blades. With anvil shears, a sharp blade comes down on the flat edge of an opposing blade. The flat edge is soft metal so as not to dull the opposing sharp edge.
Bypass shears, in contrast, work more like scissors, with two sharp blades sliding past each other.
Anvil shears generally are cheaper than bypass shears, and the price difference is reflected in the resulting cut. Too often, anvil blades crush part of the stem at the end of the cut. And if the two blades do not mate perfectly, the resulting incomplete cut leaves the severed stem hanging by a thread of bark. That wide, flattened blade also makes it difficult to get the tool right up against the base of the stem you want to remove.
Because a pair of hand shears is such a useful tool - one you might drop into your back pocket each time you walk out to the garden - check out weight, hand fit and balance before settling on one. Can the blades be removed for sharpening or replacement? A bypass pruner should have an adjustable tension screw so the blades can be made to close easily, yet be tight enough not to bind on a stem.
Size and other features
Some shears are tailored to fit small hands or left hands.
The blades of some bypass shears are hooked at the end to help prevent a stem from slipping free of the jaws as you cut. Other shears achieve the same effect with a rolling action of one bypass blade along the other as the handle is squeezed. A ratcheting action makes it easier to slice through thick stems, but you do have to squeeze repeatedly for a single cut.
Shears might ease hand strain by having grips that rotate as you make the cut.
Give any pair of pruning shears care and it will give you years of service. Dirt can nick or dull sharp edges, so give the blades an occasional wipe with an oil-dabbed rag. Clean off sap with a rag dipped in a solvent such as kerosene. Periodically apply a few drops of oil to the bolt that joins the blades, as well as to the spring that spreads the handles.