I am one of those people who asked for a Bank Simple invite. At the time I had an account at a bricks-and-mortar bank. Since then I have switched to ING Direct and in some ways I am a harder sell. But I will say this: UI does matter. It's not just about the fee structure. However it will have to be an awesome UI (by which I mean the money management layer available to the customer) to get me to switch again