Service and value - a lot of highstreet banks are staffed by idiots I find and if my bank manager is younger than I am I'm questioning the hell out of the caliber of people they aim to hire in order to manage my money for me.
I have a current account and savings account with HSBC and do all my business banking with them, I also support my local credit union. 3 credit cards with other companies but I rarely use them.
People were all up in arms a while ago about HSBC "Oh they launder drug money" well more power to them, someones got to launder the drug money haven't they? If we capitalise on every other aspect of human wants and desires, why not drugs.
Had endless problems with Nationwide and Natwest, briefly did Lloyds, all of them wronged me in some way so I said sod them, I'll take my money elsewhere.