The best part about NLP4J is that it's free! And not only is it free, but it's open source as well! I've been using this software for quite some time now and have never had any problems with it. It's very easy to use and has a lot of features if you know how to use them. There are a few things that can be improved upon. For example, there is no way to change the amount of output data you want to display. However, this is something that could be fixed by adding more options. Overall, I highly recommend this software as it's simple enough for beginners yet powerful enough for advanced users. I primarily use NLP4J to solve word classification problems and I'm able to achieve high accuracy rates with minimal effort.