It's basically an AIB Mastercard - so all your dealings will be with AIB. Generally their customer service is quite good (or at least I've never had an issue with them when I've called)
Thanks a million had an AIB card in the past and only swapped it to UB to get 0% balance transfer and had a nightmare with them cancelling the card randomly once when I was away and a number of other problems when I cancelled it! Never had any trouble with AIB so fingers crossed.