For whatever reason I have much better luck with Google Now on my Android phones (currently a Nexus 5) than I ever did with Siri. Something about my English/American accent threw Siri, and it would take several tries to do anything, so I just gave up using it. Google Now isn't perfect either, but it's much, much better. I can quite reliably talk out text messages and do searches.
My Google Now moment was when I was in Europe: it automatically reminded me of the time back home, gave me the Euro or Pound exchange rates to the dollar, a few phrases in French, and looked for nearby things to do.
This video from PhoneBuff shows the range of things Google Now can do, pretty impressive. I'm only using a fraction of these. Still, combined with the info cards that Google Now preemptively creates throughout each day, it's a genuinely useful feature that I check out multiple times each day.