Either. I've only seem the Strike King. The old woman in the club uses it. She's not a starter, but her arm isn't being nice to her anymore so, and it just weighs 12 pounds.
She throws pretty straight and slow, she gets a few strikes with it.
(Throws it on the second mark to the right, most of the time)
While you're bowling with the one you choose. Study how you bowl.
Do some research on Stroker, Tweener and Cranker. Styles of bowling.
Stroker, which I am, throws the ball straight and with little hook. I throw the ball at around 13 mph/20-21 kmh.
You could always record yourself bowl later, then post it on here for more help. I also recommend becoming a member of the facebook group Bowlers Uniting, if you got an FB profile.
The PSO I go to recommended me the Roto Grip Sinister as my first ball, I had been bowling with a hand me down Slingshot. Got it from the old woman using the Strike King.
So maybe the Roto Grip Menace would be a good starter ball too. The Menace is Sinister 2.0.
RG say the Menace fits any style.