Yes, they've great selections, but you will most likely get caught for Customs Duty, most likely VAT when it arrives in Ireland.
There are good calculators available, just search: duty calculator
Have you considered buying the designs through Etsy to print in Ireland or through an online printer? Buying the full print ready designs is great value and then you can professionally print in Ireland to save a lot!
This is what I (almost) did. I designed our invitations and printed through VistaPrint and Print24. Will be launching my Etsy store soon that will sell fully designed invitation collections that you can download