Comparing taxes is hard. There are various other 'hidden' taxes that Ireland doesn't have. e.g. no 'council tax' or property tax (though they are bringing one in, most likely just for people who own, not rent), there are no water charges (yet), etc. All of this can mean that someone can have more in their pocket at the end of the month in Ireland. It all depends.
Ireland's cost of living has been in decline in recent years due to the recession triggered by the global credit crunch and a substantial local property market collapse. For example, this is from 2009:
And between 2009 and now, our economy has been flat at best. I think it's important to look at all of these factors when examining a country's economy. The real problem Ireland has is unemployment: we went from ~4% to ~14% unemployment in just a few years. This has added to the decline in the cost of living however (less demand for goods and services).
The unemployment rate is sorta higher, but is hidden by a lot of unskilled labour emigrating abroad for work. Irish culture has a history of accepting emmigration to find work when things are bad.
Rent and property have also fallen in value, making it cheaper to rent.
