Use Reeder, Feeddler, Fiery Feeds, Lire or Web Subscriber on iOS, FeedMe, Gravity, NewsJet and Vienna RSS on Mac.
Unread on iOS, Readably on Android and ReadKit on Mac can be used by setting bazqux.com as a Fever server (see how to).
BazQux Reader supports both Google Reader and Fever APIs.
Please, tell developers of your favorite client app to add support for BazQux Reader!
API documentation is here.