Classic Spriest or Warlock for pvp?

I'm looking to play a new class for shadowlands - either warlock or shadow priest. Which do you guys prefer for pvp and why? I've tried them both a little and found that I like shadow priest a little better because they don't have to sit there and cast as much so it's harder to get spell locked. Priests also have dispersion for when you get focused. Lock for me just doesn't seem to have much mobility and get locked down pretty easily, but people were telling me to go warlock. Just a casual player, Any advice you guys can give I'd appreciate. via /r/wow https://ift.tt/2I87fSZ