In my case I use a method similar to TSW (www.thesecretweapon.org) to implement the GTD method into Evernote, and Evernote is where I keep everything, so I have no use for other Reminders such as the iOS Reminder, using this recipe you can turn your iOS Reminder in Sync with Evernote simply to use Siri built in features with Evernote.
Explore more great ways to automate Evernote and iOS Reminders