Or, to be more specific, the pros and cons of different kinds of academics who could be your examiner. Almost every good quality that you could value in an examiner, might be a negative for someone else.
An expert in my field!
“They’ll really understand what I’ve done!” versus “…they’ll… really understand what I’ve done… Oh… Hmm…”
Someone I cited a lot in my thesis!
“They can see what I did with their work!” versus “…what if they don’t like what I did with their work?!”
And so on. There’s no right or wrong really. Qualities you find helpful are your preference. Think about them and get a list of criteria for what a good examiner would be for you. Then think about who might match the list you have. You don’t get to choose, but can suggest names to your supervisors. They’ll probably have their own criteria and ideas too, so it’s worth preparing for a conversation.