Hi Siri, Ok Google.
No doubt, Google Assistant is the best intelligent voice assistant today. She has given a chair in functions compared to Alexa and above all, Syrians (Cortana does not count).
Now, the position of the Google Assistant to Apple Platforms is a bit complicated, obviously, because they do not want this "intruder" on their platforms.
In this way, it works in the form of an application and widget, but it can not be part of the operating system, as in Android, which is super convenient.
Google now seems to have the stick to the cat and found a way to get involved in iOS, though there is a sort of "hack", not a very elegant solution.
The latest update gives you the option to add a shortcut to Syrians that takes you directly to Google Assistant, so using the voice, it would be something like: "Hey Lord, Ok Google" and Voila, get the best assistant.
Anyway, playing a bit more with the recipes, you can add any action you need to assist with the phrase you can think of.
For example, Syri is not very good at understanding English, so if you ask for sports scores of NBA teams, it's not really good. Now you can say "Philadelphia," what you understand, so open assistant and looks for "what time the 76ers play and it works.