Quantum computing could very well be the next big thing in the tech world. One of the companies at the forefront of this computing revolution is quantum processing unit (QPU) maker Rigetti Computing (RGTI 9.77%). Here's why I think investors should forget Rigetti (at least for now) and consider an established AI giant that's a much safer play instead. If you think quantum computing sounds futuristic, high-tech, and incredibly complicated, you're not far off. More than 210 clients -- including Boeing, Wells Fargo, the Oak Ridge National Laboratory, and the University of Southern California -- use IBM's quantum computing services.