I switched to the Santander 123 account a year ago and I have been very impressed . The interest rate and cashback on bills is very good. I was with barclays for over 20 yrs and I should've changed years ago. The difference from Barclays is like night and day.
The Santander staff are so friendly and helpful in the branch and on the telephone. My workplace started banking with them last year too and I have had to contact them on occasions and their business customer service is just as good. :)