Dublin vs Galway

I was in Ireland and much preferred the Western Coast, so I’d say Galway. Dublin was fine and had stuff to see too, but I think you could do plenty of reasonable day trips out of Galway. Probably depends on what the types of things you want to see and do. We stayed in Galway for three nights but mostly and used it as a base for trips to Inis Mor, Connemara, and the Burren. We didn’t actually spend much time in Galway itself.

I've been to Dublin four times and Galway two times. I love both of them.

Both cities are worth a visit. If you want culture, energy, and history, Dublin is the better bet. If you want atmosphere, views of the sea and friendly pubs, Galway is the better choice.

Having said that, I believe days trips are better from Galway. You can rove up and down the west coast of Ireland and visit the Aran Islands. However, Dublin is a world unto itself, sporting dozens of sites within the city and via day trips worth doing.

We really dislike Galway. It's the second most touristy place we've ever been to, surpassed only by the Cinque Terre villages. But it is scenic.

We stayed in Limerick and found it to be an excellent headquarters for visiting the south of Ireland. Great food, convenient highway access, reasonable prices. It's certainly not a tourist Mecca, though.

This question would be easier to answer if you indicated what your interests are, how long you'll be there, whether you intend to rent a car, etc. The best way to allocate your time is to make a list of sights and day tours and estimates of how much time each one takes. For example, if you want to do a day trip to Glendalough (or Newgrange) from Dublin, you should allocate a whole day for that.
Much is changed in Ireland since you were there before. EPIC (couple hours/half day) is a very good museum, though quite crowded in June. East of EPIC, the Docklands are has seen enormous development in recent years and has loads of restaurants. The Book of Kells "experience" (couple hours/half day) has expanded. Also, very popular and requires timed entry just about any time of year.

I was in both cities in early March of last year. As a city, I prefer Dublin to Galway.

Dublin has much more to offer and really great rail connections. My favorite museum there is the National Archaeology Museum. I've done day trips by commuter rail to Malahide, Howth, and Dalkey. The last two towns were my favorites, and I have been to each one of them twice. I have also done a day trip to Glendalough and Kilkenny with Collins Day Tours, which was very enjoyable. I have been to Dublin twice and would definitely return again.

As for Galway, I enjoyed the two day trips we took with Lally Tours (Cliffs of Moher and Burren Tour and Connemara National Park and Diamond Hill Day Tour). However, I didn't care much for the town itself. We were there on the weekend, and it was overrun with a party crowd. It was over a week before St. Patrick's Day, and there were already international travelers there ready to drink their weight in Guinness. Because the town is so small, this is hard to get away from.

As a side note, I stayed a few days in Cork in 2019 and loved it!

Galway City is very much on the map now and does tend to get very busy. People either seem to love it or hate it. TAs a base for day trips around County Galway, Connemar, Aran Islands, Mayo or the Burren, it can't be beaten. However you really do need a car to see the very best of these.