I like how easy it was to use. My recommendation engine has been up and running within an hour! The documentation could improve by adding more examples and explanations. Also, there are no tests included so you have to rely on my word when using this software. As far as speed goes, its pretty fast considering the amount of data used in some cases. It's not perfect but worth taking a look at if your looking for something simple yet powerful. We needed a way to recommend items to users based on their previous purchases.