A patio cover can provide shade and will allow you to use the patio more often. It can also protect against rain and you can leave outdoor furniture outdoors even in the rain.
Think about the design and size of your patio first and decide whether you want full shade or light to transfer through the patio cover. Don't forget about heat transference. It may be better to spend more on a patio cover that is insulated so you can feel comfortable in the patio even on the hottest days and the insulation will help dampen noise from rain.
You can also use a combination of materials or choose different colours of polycarbonate sheet to make the patio more appealing.