Use VAT / FEXCO Horizon Card?

I've never used it (always done the refund myself). But one point I notice: "Swipe your HORIZON Card every time a purchase is made in any of the affiliated stores.". Looking at the list, this card only works in Ireland, and only in a small list of upmarket shops.
"At the FEXCO Kiosks in the departure areas at Dublin, Shannon or Cork Airports." - I.e. this card only works if you exit the EU through one of these airports.

That trip Savvy report is talking about the UK, but you can claim back VAT for purchases in any EU country.
The rules for VAT refund are:

• You must not be a resident of the EU.
• The goods most be exported unused and intact in their original packing. You cannot claim back VAT on anything you use, or consume before leaving the EU.
• You can only claim back VAT if the shop is prepared to do the extra export paperwork. "or if I should just save receipts" - that won't work, you need to get export forms from the shop at the time you buy the goods. Not all shops are prepared to do this, just those that have a large number of non-EU tourists as customers.
• When you leave the EU (not necessarily when you leave the country you bought the goods in), you must go to customs to get the export forms stamped to prove the goods left the EU. Customs may want to inspect the goods, so you must have them with you.
• You then return the stamped forms to the shop (or their agent, it should say on the form). The form is proof the goods were exported, so the shop does not have to pay VAT to the government for the goods, so the shop can now refund the (over-paid) tax to you, less a handling fee.

If this sounds complicated, it can be. It is only worth it for big purchases.

Actually, we used those cards at quite a few shops throughout Ireland, and got a nice refund at the end of the trip. I think my refund was about 80-90€, and my mom’s was maybe the same. Definitely worth it!