Avoid the obvious glare
Position task lights to illuminate paper or a keyboard without reflecting off a monitor. Diffused light is often more pleasant than an exposed point source close to the eyes.
Adjustability can be more useful than peak brightness. A light that can be moved low and to the side works for more tasks than a fixed light that is simply very bright.
Color and color temperature
Cooler settings may help with detailed work, while warmer light often feels more comfortable in the evening. If accurate colors matter for design work, review color-rendering specifications rather than relying on vague ‘studio quality’ claims.
Check final specifications and compatibility with the manufacturer before purchasing. Catalog items shown here are illustrative.