When comparing Siri vs Cortana, the Slant community recommends Cortana for most people. In the question“What is the best intelligent personal assistant software?” Cortana is ranked 2nd while Siri is ranked 3rd. The most important reason people chose Cortana is:
You can ask Cortana what music is playing and she will attempt to identify it.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Good at composing messages using voice
Instead of taking every word literally notes such as "comma", "question mark", etc are taken as instructions.
Pro Identifies unknown callers from emails
If an unknown number is calling you, Siri will try to identify the caller by attempting to match the number with people you've had interactions with over the email.
Pro You can talk with Siri
Pro Can look up information on the web
Pro You can manage your tasks and calendar
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 News suggestions aren't personalized
Instead of showing news suggestions tailored specifically to you based on things like search history, Siri shows only news that are trending in your area.
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.