Hi I have used WEKA back in 2010. So Im not quite aware of whats happening now. But all I can say is when I used, I found it quite an effective tool for data analysis. But some times it lagged for heavy data that time
A well documented, fantastically easy to use set of resources/toolkit for machine-learning work.
Weka is a collection of data mining algorithms that can help us in several tasks
Blanca A. Vargas Govea
I have used it (and I am still using it), and I have great experience with it.
Easy to use, with many algorithms, well designed, easy to extend using Java. Very useful to use in the Java ecosystem.
It's the best tool for using ML in your research, very quick to try different classifiers or feature selection.
It implements a large array of machine learning algorithms. Its interfaces make it easy to use, especially for teaching or explaining.
... it's a rich resource of machine learning algorithm implementations, feature selection methods, meta methods and ensemble methods. It also allows automatic selection of the best algorithm and its hyperparameter settings for a particular dataset through the Auto-WEKA extension (www.automl.org/autoweka).
It is easy to use in you own code and algorithms. Besides, it contains many algorithms itself.