I've long been a fan of Shazam – I use it daily to discover songs I hear on movies and TV shows. Version 9.4, just released on the App Store, finally brings a way to keep recognized songs available on all devices through a Shazam account.
Over the years, I've lost hundreds of tagged songs between clean installs of iOS and Shazam. It's good to know this will no longer be a problem. Version 9.4 has currently rolled out for Shazam Encore only, but I assume the free Shazam app is getting an update shortly as well.