I get it when im at home visiting. Pretty much have 4g coverage anywhere in the city center and in my folks gaff u p in the hills. Was in Rosscarberry last weekend and had 4g coverage in parts.
I've 4G with three in and around town and out South Douglas Road. Though to be honest it doesn't seem to be appreciably better than 3G. The main reason I'd know is that the phone says it's 4G. But it's free for the year so not complaining
It's been live in Cork about 3 years in some places. The em early sites were all 800MHz sites but some phones like the iPhone 5 only did 1800MHz 4G. The iPhone 5S does both frequencies.
Are you a former O2 customer ? If so, you need to contact 3 and they will enable it for you. i had to do it last Monday. I get up to 80mbs now on speedtest, was getting 5-13 before with 3g.