There are a lot of fundamental differences between Visualforce Page and Lightning Components:
Visualforce Page:
1. Page-Centric Model.
2. Most of the processing takes place on the server-side.
3. Applications are divided into pages and each page is an independent entity.
4. The server connects different Vf pages so that they can share data.
5. Primarily for Desktop.
6. Interactivity limited without javascript.
Lightning Component :
1. App-Centric Model.
2. As server calls are expensive, we call the server methods only when it is absolutely necessary and rest of the manipulations are performed on client-side using Javascript.
3. Applications are built with components and multiple components assembled together to form an app.
4. Events, Attributes, and Methods can help communication between two Lightning components.
5. Supports Desktop and Mobile both.
6. Highly interactive and has javascript built right in.
