It's all the same which one you get as they're all the same with regard to us roaming.
On all memberships you'll need cash credit to pay for outgoing texts and outgoing and incoming calls because membership allowances don't cover these while roaming (except when roaming in the EU on a Guido membership).
See here for details of the charges that apply:
https://www.48months.ie/membership-plans/going-abroadNote that data will not work while roaming in the US.
Again data only works while roaming in the EU on Guido.
Hope this helps.