I went with a (recommended) broker and haven't looked back. He was always on the ball and the process was rather painless overall. I'm near completion (I hope!). He was able to get me what I expected, nearly 3.5 times my salary, from Haven. I approached AIB on my own at the beginning but they offered me less than 2.5%! Reason being marital status and children. Other banks were in between but too far from the "full" amount. Without his help I don't think I would be in the position I'm in today.
I'm not in your situation though. I'm a first time buyer.