Maybe in earth's crust, but on a galactic scale carbon is more common. But they're both one of the most common elements either way, so I think other properties

Maybe in earth's crust, but on a galactic scale carbon is more common. But they're both one of the most common elements either way, so I think other properties would be more important. The way the GP comment describes carbon-based technological life made out of transistors doesn't sound like the metabolize carbon to CO2 or would require a lot of water, though, which are two important markers when searching for life.