Which is better Polkadot or Chainlink?

Could you please elaborate on the comparison between Polkadot and Chainlink? I'm trying to decide which one offers better potential in the cryptocurrency and finance space. Could you discuss their unique features, scalability, interoperability, as well as their respective ecosystems and partnerships? Also, how do they fare in terms of security and adoption rates? I'm particularly interested in understanding which one might offer more opportunities for growth and innovation in the long run. Thank you for your insights.