I would recommend Caroline McQuaid in the Blanchardstown branch of Ulster Bank. I switched over to them (although it was a regular annuity mortgage) with their switcher package and all was very smooth and hassle free (1 visit to the bank, 1 visit to their solicitor and that was it-knocked 11 years off my mortgage like that!)
I wanted a meeting with them to talk about a top-up and when I called them yesterday they were very responsive. You genuinely get the feeling they actually want your business. The same can't be said for AIB in my experience. All very subjective I know, I'm sure there are plenty of great AIB people, but I never found them to be appreciative of my business.