What do you mean by looks? Because Essentia is a masternoded blockchain. Does cardstack provide storage facility like Essentia give three alternative ways to store ones documents.
Essentia and Cardstack have different goals. Cardstack is building a decentralized software ecosystem, which offers end users a beautiful, cohesive user experience across decentralized apps (dApps) and software makers and miners a fair distribution of rewards based on usage. Whereas Essentia is more about the full ownership and control over your own identity, digital life and personal data. There is some overlap, but they are not direct competitors. We would encourage you to research and form your own opinion of the differences, as we do not typically engage in deep comparative discussion.
Plus afaik Cardstack isn't limited to working with Ethereum. Cardstack is a framework for bulilding dApps and creating a cohesive user experience. Using Cardstack plugins will be able to connect with other blockchains and cloud services. It's not restricted to ethereum.