We already have our personal computers.
We humans are sentient by any definition and have our own built-in computers. The brain has some eleven billions neurons, depending on what kind you want to count. The newest part of the brain (some 100,000 years old) is the cerebral cortex, the part that looks like a great cauliflower.
Where has that sentient biological computer gotten us?
Well, it's given us great things, beautiful and elegant things -- the special theory of relativity and Schubert's Scherzo in B flat major and the concepts of peace and neighborliness.
It's also given us televised beheadings, Social Darwinism, an arsenal of nuclear weapons, and Rush Limbaugh.
Life under Colossus and Guardian would have been dull in some respects and we would have yielded our "freedom" to destroy as we pleased. I'm not sure that would have been such a great loss.