I can't recall the last time I used Siri on my iPhone, or anyone else I know, for that matter; however, I've used Google Now on an almost daily basis on my Nexus 7. Execution is key.
I think when parent(s) were remarking on execution mattering they were implying: 'Execution is key ... to the success of the feature (and consequently) the brand'. My experience is very few people know what Google Now is. Your preference of it does not demonstrate an example of that sort of success-due-to-execution that other posters are suggesting Apple's products exemplify.
I've even found myself thinking 'Siri, where's my phone?' when I can't locate it in my flat. Siri is addictive if you learn to use the tool.
I also use for "what's the weather like today"
very convenient, give it a try, it's great