Siri seems to be designed to amuse the easily entertained. The cutesy responses, the rather limited usefulness, makes it seem like a waste of time.
Google Now is far better, designed and fully integrated in the highly useful Google Apps / Products ecosystem it's a great solution.
I have the entire set of Google Apps for iOS, on my iPhone 6S Plus. Thanks to Google it greatly improves my iOS experience. While it's still lacking compared to my Stellar Nexus 6P, it's the best way to get the most from my iPhone.