I have had dealings with NIB on mortgages in the past - 3 restructures in about 7 years. What I would say is that they are as good/bad as any other bank on service.
However, where the broker is coming from was the last 2 months where the bank took a shipload of new customers in on Fixed Mortgage offerings that were a no-brainer in that they were lower than most other bank's variable/ECB tracker rates.
This should have somewhat eased off because they increased these rates, albeit to still very attractive rates.
Might I suggest that you deal with their College Green Branch, where I know I had no hassles?
It is true that for years NIB did not deal with brokers, a legacy of the scabby previous owners NAB. May well now deal with some brokers.
Once in, you can view your account with E-banking, and if you want, you can make fortnightly payments which vastly reduces your interest bill overall - you are effectively making 13 months payments in a year, but also less time between each capitalisation of interest.