Never personally used ShiftHosting, but from what I’ve seen floating around - they claim to offer full root, CentOS, and decent resources. Whether they deliver consistently? Hard to say. Like with any VPS play - start small, test the node, and see how support responds when you ask for something weird.
Setup help? Depends on the host. Some offer basic hand-holding, others drop you in the deep end. If you need actual assistance, either pay for a managed plan.