Since the Seoul Challenge update, the app crashes for me when I try to open it, so I can only accept lessons from my computer.
Also, as a previous review mentions, there is no way to accept payment and transfer your paycheck to PayPal via the app. This might be for security reasons, but it’s worth knowing if you’ve never used the app before and I must admit it is inconvenient.
Otherwise, it’s basically everything that’s on the website that I bother to look at, so as long as I can access the app, it’s fine.