When comparing Google Now vs Cortana, the Slant community recommends Google Now for most people. In the question“What is the best intelligent personal assistant software?” Google Now is ranked 1st while Cortana is ranked 2nd.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Will let you know if a shop near you carries a product you've researched before
Pro Cloud-based speech synthesis
Cloud-based speech synthesis is nearly indistinguishable from a real human. Also, starting from Android 7.0 Nougat, users can alter the pitch of Google Now's voice. Studies have shown that higher-pitched female voices are considered more attractive by the majority of the population.
Pro Integrates with third party apps
Third party apps can use Google Now cards for notifications.
Pro Provides tracking information for packages ordered online
Pro Can remind you of upcoming TV show episodes
Pro Can look up information on the web
Google Now can answer question by looking them up on the web for you. In cases where it fails to find the answer it will direct you to search results.
Pro Automatically pulls flight information and offers relevant related information
Google Now automatically pulls information from Gmail about upcoming flights and lets you know if the flight has been delayed, how long before a flight you should leave to get to the airport on time, offers hotel options, informs of relevant currency exchange rate, as well as suggest places to visit when on location.
Pro Will remind you of upcoming events
Google Now will remind you of events that you have added to your calendar and reminders you've set using Google Now.
Pro Can recognize music
You can ask Cortana what music is playing and she will attempt to identify it.
Pro Will let you know when artists you're interested in play in your area
Cortana monitors your Bing search history, social network actions, music played, etc to find out what are your favorite artists and will let you know if they plan to play in your area.
Cons
Con On-board Speech Synthesis
Sometimes, when you have a poor internet connection, or Google is being lazy, you'll get the on-board speech synthesis instead of the silky-smooth cloud-based speech synthesis. It's very good, but not nearly as good as the cloud-based voice.
Con Non-relateable as it has no personality
Unlike many other virtual assistants, Google Now does not attempt to have a personality. It's very functional and to the point.
Con Functionality is limited on non-Windows devices
While Cortana is available on Android and iOS, certain features on those operating systems are either limited or non-existant. For example, there's no hands-free voice activation on iOS, and on Android it's only available on the homescreen and nowhere else, etc.