What are the main differences between view handlers and view plugins?
Can anyone show me what a view handler can do that a view plugin cannot?
The difference is summarized in the first sentence on About Views plugins:
In Views, a plugin is a bit like a handler, but plugins are not directly responsible for building the query. Instead, they are objects that are used to display the view or make other modifications.
A view handler is implemented using a class derived from the views_handler class, which has methods to build the query, or to alter the result obtained from a query, such as: