I'm with Ulster Bank myself on a tracker rate of 2.85%. Their only advantage over NIB is they cover all legal fees if you transfer your mortgage, but you also have the downside of a monthly fee (€8) for their U-First account.
As far as I know NIB offer the best tracker deal @ 2.79%, but they don't pay brokers commission so it doesn't get the publicity it deserves. NIB offers free banking also, a rare thing these days.
I believe NIB have recently launched an offset mortage product, which nets the balances of all your accounts together for interest calculation purposes. Does anybody know if the 2.79% rate applies to this product also?