This topic came to my mind after several ill-treatment customer service relation I had with some personnel of GTbank few months ago after I opened a current account with them. I already have a saving account I have been running since 2007, but due to some transactions I needed to do which will involve payment and clearing of cheques, I was advised to open a current account. But lo and behold, after I submitted names of my referees who even happenned to be account holders of GTbank to make contacting and verification easier. The bank failed to verify details of the referees I submitted for months. Unknown to me the account was opened to receive payment but I didnt know that I won't be able to make any withdrawer out of it since it was not yet verified then. I kept going to the branch of the bank day by day and the normal response of the Customer service personnel was that ''they will send mail to the section handling verification of referees''. Atlast, the account was opened for transactions after about three(3) months and the annoying part of it was that none of my two(2) was neither contacted.
Diamond bank also is a NO for me when it comes to good customer service handling.
Skye Bank is better to an extent

Feel free to share your own experience(s) too.