The brain evolved over time whereas computers are designed by humans and become more powerful over generations.
Currently, the human brain is still orders of magnitude more complex and powerful than any computer, but in a few decades that might no longer be true as computers continue to become more complex and powerful. We take in so much sensory information and then constantly maintain balance, thought, organ function, movement, etc that is currently beyond any computer's capability.
There are already some areas where computers beat the brain. Permanent memory is one of those examples. You can download the entirety of Wikipedia or the entirety of Encyclopedia Britannica on a small fraction of your computer and reference it whenever you want. All countless cumulative posts on RF are stored in a server database. The brain can't come anywhere close to that level of perfect memory.
Similarly, computers have immense focused working memory. Supercomputers can model situations with millions of variables following complex equations, like fluid dynamics or the movements of stars and galaxies, that the human brain can't even begin to keep up with.
So which one ends up being more interesting and powerful depends on the application.