How fast is Mvp4g compared to GWT Handler Manager?
You can look at this page Mvp4g Performances that compares Mvp4g and GWT Handler Manager. As you can see with the result, Mvp4g event bus processes events faster than GWT HandlerManager. However time to process a few events is almost equal to 0 for both event bus and in most cases applications won’t send more than 1 or 2 events at a time. To sum up, you can use Mvp4g without worrying to make your application slow.