I have had my account since it was the Midland Bank!
I have used NatWest and a couple of others, but overall, I like HSBC; they have always answered the phones quickly, they have always been courteous and I have always been helped where they felt they could assist me.
My only grumble is that recently I went in with my shopping trolley and couldn't get upstairs to use the counter service due to the lift being out of order; I asked the security man on the ground floor if he could just watch my trolley for a moment whilst I attended to my business upstairs but he refused stating security issues - my trolley was completely empty! I hadn't started shopping for the day at that point.
The good thing is that there are now automated machines which let you pay in money without queueing for a counter assistant.
Overall, a good bank - at the moment, thought they are going through a lot of changes by the looks of it and that may not be to everyones advantage ultimately.