Best Latex Primer for Old, Clapboards?

[MassWineGuy]

Getting ready to finally paint the north side of my house. I’m only spot priming bad areas and top coating everything.

What’s the consensus on the best primer to use for rough, uneven surfaces that are prone to mildew? I’m thinking of California Paint’s Trouble Shooter or Zinsser Bulls Eye 1-2-3. Good adhesion is important. Trouble Shooter is twice the cost of the Zinsser.

Thanks.