The link Rachel shared from SO about MVP vs. MVC goes into a lot more detail, and is probably the definitive answer to your question. I believe
RAD in that question stands for
Rational Application Developer, which is an IDE based on eclipse.
They are fairly similar. From my experience, the particular variant you end up using is in part dictated by the framework you use and which pattern it is geared towards. WPF and Silverlight, for example, really emphasize an MVVM approach which is a variant of MVP.
Other languages / programming stacks will push different MV* variants. Use what's native to your stack.
The link Jeff O. posted looks at the question from an MS ASP stack point of view.
For some additional info, look at Martin Fowler's discussion of GUI architecture. This paragraph comes from the beginning of the MVP discussion.
To approach MVP I find it helpful to think about a significant mismatch between two strands of UI thinking. On the one hand is the Forms and Controller architecture which was mainstream approach to UI design, on the other is MVC and its derivatives. The Forms and Controls model provides a design that is easy to understand and makes a good separation between reusable widgets and application specific code. What it lacks, and MVC has so strongly, is Separated Presentation and indeed the context of programming using a Domain Model. I see MVP as a step towards uniting these streams, trying to take the best from each.