Particular nits are: - pressing the browser 'back' button triggers an immediate logout - they don't use email for anything except to tell you they've sent you a "secure message" that you have to log in and read - no data export (though there are greasemonkey scripts)
Their customer service I've found to be fine unless you want anything usual, complicated, or to be done in a timely fashion. Much like any large company, really
For example, I can pay in a cheque or withdraw funds over the counter in a Coop Bank branch, but if I want to set up a foreign bank transfer I have to use the an online secure message. When I asked why I was told over and over "smile is an online bank". Which I suppose is true, up to a point.