Windows Central reviewed the Backbone One Controller
A quote from the article:
The Backbone One is the best gamepads for iPhone, but with clever use of iOS features, it doubles as a slick gaming platform you won't find elsewhere.Backbone One Controller Review
The rise of cloud gaming has driven a new era of mobile gaming accessories for smartphones, many imitating dedicated handheld consoles, albeit some more viable than others. The Backbone One is among the latest breaking into the space, and with Microsoft expanding its game-streaming tech to iOS, there's a compelling basis for its $99 asking price to Xbox owners.