I have both, Amazon Echo mini and Google Home (not mini)
* Volume/clarity - both are great, impressed by the small mini, of course the GHome wins as it's bigger here
* Plugins with other apps - this depends what you want to do, for me, Ghome wins because it can access my Google Music, it also has spotify and heaps of other services too
* Chromecast control - only google devices can do this, and it's great!
* alarms/reminders/calendar - google wins here
* location setting- you CANNOT tell Alexa you're in HK, so, whenever you ask "weather tomorrow", you need to say "weather in hong kong tomorrow" ... google you can tell it where you are and it remembers
* integration with my home assistant (https://home-assistant.io/) google works better here
* IFTTT - seems to have tighter integration with Alexa
throw your questions at me!