SUTime is very good, like all the StanfordNLP stuff. We chose to do Duckling because: - To my knowledge SUTime only supports English - We wanted something tha

SUTime is very good, like all the StanfordNLP stuff. We chose to do Duckling because: - To my knowledge SUTime only supports English - We wanted something that's easy to extend. SUTime is somewhat hard to extend, especially if you are not into Java - We needed not just temporal expressions, but also monetary data, temperatures, quantities... That being said, Duckling is still young and certainly not as proven as SUTime yet.