I use almost all of them. Alexa, Siri and Cortana - in smart home, PC and telephony - especially in the car. My car and phone are really well integrated and that's sorta why I picked that particular car - it's just Carplay (or Android if you have it) but the cabin noise, built in mics and speaker system make it a fantastic place to make and receive calls, so I sometimes schedule phone meetings for commute for that reason. Once or twice I've gone out to the car to make a call if it's while I'm home.
Carplay is very strict on functionality for distraction - my car can for example post and read Tweets, but that's not supported in Carplay, probably just as well I guess. But I briefly enjoyed tweeting ridiculous car observations while testing it. "Oh surprise, the Mercedes G-Wagon camping in the passing lane didn't signal before swerving illegally into the carpool lane"
At home it's mostly Alexa for music, radio, AV control, lighting, thermostat etc, but the kitchen is where it shines. Timers, recipes, proper alarms ("Remember to turn the oven down to 325 degrees") measurements, conversions, ingredient suggestions - I've never ordered supplies, but there's no reason I shouldn't. The fact that you can do all of this without touching anything -phone screens and cross contamination are a serious practical as well as safety issue - and so I can reduce even hand-washing by more than half. I know that sounds probably pretty dumband trivial but as the main cook in the house, it's fantastic. I use an Echo Show there, so recipes are always visible and I can see multiple timers as well as hear them.
I've tried using them for full AV remote integration but my setup is a bit too convoluted for that and since I'm flighting or testing Xbox system updates, I can't rely on every component and preference staying put, so I kind just use OneGuide and voice for power and volume basics. Also, HDMI CEC is really fussy and unpredictable for timing - so you can end up getting out of sync very easily.
On PC, Cortana for scheduling and multitasking has been great. I don't use Google Home but I would if I used more of their stuff generally. I used to get names mixed up but once I started thinking of them as people, that went away. I am also unfailingly polite to all of them because scientists keep teaching robots to do stuff like climb stairs and brekadance - and they all have claws. So it's just an investment in my future safety. I literally say thank you to them. That's also on plan with teaching my badly behaved guttersnipe kid some proper manners.
I also secretly enjoy long texts with emergent or hilarious "typos" which I guess we should call "speakos?" Or "voice-os?"
Tip for Apple etc:
Let me customize granular Carplay steps so that I can eliminate the need for Siri to repeat certain steps or transcriptions back to me, and so that I can cut out needless repetition and steps as an "advanced" user. And loosen up on Safety or at least align with other manufacturers. In fact I think on safety - there should be some serious alignment. Touch screens in cars are fine - especially for passengers - but I drive a car with two big OLED screens with NO touch functionality - and the upside is that the car's ergonomics for safe touch-based, non distracting controls are FANTASTIC. I worry that enabling touch on the newer models is going to reduce the effort that went into that. And with it, safety.
After about a month, loads of things that seemed weird at first all clicked into place with a "ooooohh yeah! That's why touching that button makes the UI element light up without activating it! SO you can sense things withhout taking your eyes off the road."
Edit. Final confession: I didn't know Echo Dot had a reasonable (radio, alarm clock etc) speaker for two months after getting one. They have one without a speaker now for cheaper integration with your home speakers - and Alexa Echo Auto will be an absolute GAME CHANGER for folks with older or more basically equipped cars - it's literally going to save a few people thousands of dollars in trim level by giving them a lot of functionality with an array mic that can hear over road and car noise, integration with their phone and Amazon services, that might otherwise cost a fortune for the loaded model.
