I haven't had much contact with customer support but I've never had too bad an experience. I really don't like Bank of America's customer service though. In Arlington they just hire incompetent old Indian ladies who made setting up my account really hard.
RBC on the other hand has had very good customer service. My debit card was compromised a couple months ago and they made it very easy to get it fixed. I've also had to deposit a couple big checks from American to Canadian dollars and they have made that simple as well.