"Hey Google, Ask Alexa What Siri Is Doing."
"Ambient computing." For decades it's been a staple of what the future looks like. Although not explicitly named, ambient computing is what we would now call Captain Picard (or Kirk, if you prefer) barking commands at the Enterprise. It's the once-helpful-now-intent-on-destroying-us interactions with HAL in 2001: A Space Odyssey. Ambient computing is, at its core, an omnipresent digital entity forever at our beck and call.
For most people, Apple's Siri was their first exposure to this type of interaction. (Although initially, Siri had to be manually initiated via device interaction; always-on wake word listening would come later.) Amazon's Alexa then became the big name, thanks to a variety of factors: Foremost, Amazon's ubiquity in modern life, and the marketing power that entails. Google's Assistant could be argued to precede Alexa, but for the sake of argument let us consider them contemporaneous rivals. (And in the interest if simplicity we won't even discuss Microsoft's Cortana, as it's unclear if even the good folks in Redmond know its purpose at the moment.)
Which one is the answer for your home or office? Right now, that's probably not the correct question to ask. Rather, what is your operating system (OS) of choice? If you're reading this post on an iPhone, then Siri is probably your best bet. OS-agnostic, or have an Echo device or two in the room? Alexa is the natural gravitational pull. Android enthusiasts have likely already made their choice in the form of Assistant.
Let's return to our original question: Are any of these assistants actually providing assistance? As alluded to above, it's a bit of a draw at this point. Each service has strengths and weaknesses, and there is no clear winner right now. They all can help, but are all restrained by the limits of current technology. Ambient computing is here--and it's real--but it's not yet the future we've imagined.