[BrianEatWorld]

I used it for a solid year when it first came out and have recently switched to Android, so that I can use Project Fi.

I found the systems to be pretty comparable. Google Now still creeps me out a bit because it assumes I want it to do many things without asking. This may be a product of me not customizing the options, but the fact that it has pinged me while I was sleeping to tell me I was late for a flight in a different country that a family member was taking was irritating. I didn't have that kind of issue with Cortana because it seemed to only do what I directly requested of it.

The voice recognition and speed seemed a little better than Google and Siri at the time too. During lunch, we frequently had faceoffs between digital assistants and Cortana won more than its share. It also seemed to be better at not just showing search results for a question, but actually answering it like a human would. I've even found that it's song recognition works faster than Shazaam, although it has a higher rate of returning no results.

From my experience, unless you are in the MS ecosystem, there is probably little reason to switch from your native assistant. The one exception being, if you find the data policies or certain features to be too intrusive in your current assistant.