I don't really understand the logic of some of the comments on this thread that are implying that Dublin's some kind of remote backwater.
1.) It's very well connected by air, far better than most cities its size and that can quite easily be scaled up as needed either with expansion of Dublin Airport (planned) or possibly even a second airport to the West of the City. At present it's handling more than 25 million passengers, making it the 3rd busiest airport in Britain and Ireland (placing it after LHR and Gatwick) and significantly busier than Stansted, Manchester etc.
Ireland also has huge amounts of connectivity for its size to North America and full pre-clearance arrangements with the US, meaning you effectively land as a domestic flight. Again, that's scalable up without much fuss.
2) Many of you may not realise but, software is no longer shipped in trucks on punchcards. Banking services also don't send cash in trucks or post cheques. So the shipping issues are largely irrelevant. A bunch of diverse fibre routes and excellent air connectivity, both of which Ireland has and can easily expand, is all you need.
3) Culturally, it's almost indistinguishable from England/Wales in terms of business and legal structures. The systems are incredibly similar and the business environment is very similar. On top of that, you've got the fact that the general culture is almost identical too. Moving Dublin to London isn't all that much different from moving from London to Manchester. (Yes, I know I'll have offended a few Irish nationalists with that, but it's fact).
4) It's quite a business friendly environment and the bureaucracy is easy to deal with.
5) There is no language barrier at all for English speakers.
6) It has its own visa system and can prioritise immigration for anyone it likes. This can make recruiting non-EU high end staff very straight forward if we want it to be.
7) It isn't some tiny village with a few sheep. It's a metropolitan area of 1.8 million people and growing extremely rapidly. So, in terms of scale, it's only going to get bigger over the coming years and decades. I don't really see Dublin as all that much different from Amsterdam, Brussels, Antwerp, Rotterdam or any of the Nordic capitals and even the majority of the German cities are all mid sized.
8) If needs be, Ireland can fairly easily scale up ferry connectivity directly to France. It's only about 10-12hours in a faster ferry. At present they're mostly used for holiday makers going each way, but there's no particular reason if we had to improve connections avoiding British 'land bridge' routes that it would be particularly difficult to achieve.
The only huge megapolis type cities in the EU are London, Paris and arguably Madrid. The rest are all clusters of cities in the 1 to 2 million kind of scale and the vast majority of EU cities are actually <1 million.
10) Irish-US political and cultural links are absolutely enormous and deep. It exerts huge soft power in the US, but doesn't go on endlessly about unlike a certain other country in the southeastern med. US presidential candidates still feel the need to embrace their Irish great, great, great granny who happened to visit Killarney in 1747 and Irish political figures have enormous access in the USA because of the scale of Irish-American links.
I wouldn't really underestimate Ireland in any of those areas, it bats enormously above its weight and it has a lot of attractive features for location of businesses and particularly transferring business out of the UK. You're still looking at a huge legal, cultural and language jump to go to the Benelux. Second language English speakers, civil law legal system, significantly heavier and different approach to bureaucracy (Ireland and the UK are much more similar), different media, different culture ... list is endless.
Where Ireland will suffer badly though is more in the areas of non-tech, non-financial, SMEs who have a lot of connectivity to the UK due to physical proximity e.g. small / medium food businesses, small services companies etc. Also it will cause total chaos for Irish and UK companies in Northern Ireland who have been treating the Irish market as a single entity for the last few decades. A lot of intra-juristicaonal business in Ireland will be damaged very badly. That's going to hurt the likes of retail groups, logistics companies, food/drink companies, locally-focused service companies etc etc.
So it's kind of swings and roundabouts, but I think Ireland's at a huge advantage for taking businesses that want to exit the UK post Brexit.