When it comes to hiring, focus on what matters:

"The Pint Test"

   
If the idea of us having a pint together makes you happy, then we can work together.

Are tech challenges good?
Maybe?

Maybe it just means that they are good at tech challenges.

There is no guarantee that they will succeed in your role with your company.

Being good at tech challenges != being good at the role.
Being great is all about being able to communicate.

Do you quiz your mechanic about torque specifications before he rotates your tires?

Hire someone you like.
Hire someone who is fun.
Hire someone you trust.