Both Data Science and Cloud Computing are good careers. Data Science is the future of technology and Cloud computing has already gained popularity and can continue the same. Integration of Data Science and Cloud computing can create wonders and can become new technology. As a career choice, Data Science is better than Cloud Computing based on job availability and average salary. In terms of difficultness to learn the technology Cloud Computing is better than Data Science.
If you are interested in Data Science, I would suggest you enroll in these Data Science courses by Intellipaat.