Selenium RC Vs Webdriver

Webdriver provides the alternate API's which are not supported by Selenium RC also.

It is advantageous or next version for Selenium RC.

It uses different framework underlyng it from the way Selenium Javascript uses Selenium core.

Webdriver works with the browsers directly rather than through the proxy as the Selenium RC does.
Webdriver doesnot need any server running for running the automation scripts.

Webdriver also works and interacts with different browsers like IE, FireFox etc..

WebDriver:

1. It directly works with the browsers.
2. It has simple API's to work with.
3. It has a interesting feature of Headless execution against application with HtmlUnit drivers.
4. It works with java.
5 It responds faster than the Selenium RC

RC:

1. It does not directly interact with the browsers instead creates a proxy.
2. It has support for limited browser version.
3. It supports various scripting languages.