Which is better- a clear retainer or metal retainer?

Retainer: Both have their pluses and minuses. A metal fixed retainer that is bonded into place works better for compliance because you can't remove it. It is however difficult to keep clean. Plastic or resin retainers can break and get lost but area easier to clean. It's really your choice....for the sake of retaining the teeth in place post orthodontic treatment, both work equally well

Wrong person: You're asking the wrong person. The person that knows you, your original malocclusion, and your retention requirements is your Specialist Orthodontist. Orthodontists are trained to help you choose the retainer type that best fits your Orthodontic requirements.