Yellow Card alternatives

I've been using this since the first private beta and it's been great. Fundamentally, 100% of the customers' crypto assets are kept in cold storage, making me feel like my funds are safe from hackers, and the XS2key security they've implemented means a hacker would have to have access to one of my approved devices to trade, which would basically mean holding me hostage. XS2 has been funded by the founders, not by an ICO or venture capital so I feel like it actually has the capital backing it needs rather than in theory being able to access the capital backing it needs. Simple 0.1% commission on trades for all customers, no matter how big or small. Available for iOS as well as desktop browser.