I absolutely stopped using Cortana altogether in WM10, it was so slow, takes half a minute to load anything on my Nokia Lumia 525, and I had be blinded 30 seconds with that horrible mismatched white theme. Music search too slow, wont even recognize anything now, says no internet connection. anything I search takes another half a minute to load suggestions and another half a minute to display results on what appear to be the mobile Bing site.
At this point I realized how time consuming this app had become and I stopped using it altogether. The animations are sluggish, the reaction time from voice recognition is slower than the sloth recently found on a highway. This is a totally different app from the fast and fluid and consistent 8.1 experience.
A new low for the Cortana team, who might probably be busy working off to make it even more horrible or even more awesome for Android and IOS users.