A good competitor should:
Be in the same industry.
Have a similarly sized web presence (for example, comparing your business to Amazon is rarely a good idea).
Have a presence in your region. While you can compare your performance to any of your competitors,  their score will be just for their presence in your chosen region (UK, USA, France, Australia etc.)
NB: when you start using the feature, you will see that we have pre-selected some competitors for you.  Updating the competitors that you rank against is simple – just click on the ‘Edit Competitors’ button and follow the instructions.  For more information on this, please read here.