Heck, I could 98% distrust Trump, and I'd still trust him more than almost any* of the professional pols. *I like Cruz, but what executive experience does he have? There's his stint as Solicitor General of Texas, but that doesn't fatten his resume by much...
Between Cruz and Walker is a difficult choice for me. Cruz is better speaker and excellent conservative principles, but Walker has actual record governing, balancing budgets, fighting government employees unions, and winning elections in a blue state.
However Trump would be be better than both to push hard for a bold agenda as president. Why? Because he does not have rich donors yanking on his chain and constantly pushing for the cheap labor express (illegals & low skilled legal).