There obvious costs differences between them but I am not sure from a security perspective which of them considered to be more secure.
In short: no isolation is the worst. Isolation by sandboxes is better but costs more resources. Isolation by containers is even better and costs even more resources. Isolation by VM is again better and costs again more resources. And isolation by hardware is even better and costs even more resources. Of course, implementation details are relevant and might actually cause more secure technologies to behave less secure.