rendering

server-side rendering: When the browser fetches the page over HTTP, it immediately gets back HTML describing the page.

good

1. The content is visible to search engine like Google
2. The page loads faster (relatively, may effect t_done). There's no "white page" while the browser downloads the rendering code and data and the runs the code.
3. It maintains the idea that pages are documents.
4. performance is predictable.

bad

client-side rendering: JavaScript running in the browser produces HTML or manipulates the DOM.

goood

1. can update the screen instantly when event occurs - no need to call & wait for server's response to re-render & update the page
2. improve performance - when you get enough resources, i.e., web pages & templates, no need to call server and fetch pages again.

bad

1. Loading spinner - people need to wait till they get the data
2. unpredictable performance - heavily relied on what devices people use.