My two cents:
Cost of living - Rental accomodation is much cheaper than Australia and NZ, working out of Shannon anyway, can't vouch for Dublin. Food is on a par with Australasia, fruit and vege a little more expensive, but averages out the same. Utilities a little more expensive, but a better choice of broadband and satellite. Cars are very expensive, but you are buying and selling in the same market, so your depreciation is the same as at home. The only real killer is the tax on cars. You are taxed on the size of your engine, so if you want a SUV like home, expect to pay 2000 Euro a year just for registration. Insurance is also very expensive.
Work Environment - the guys/gals in the ops room are all very friendly and welcoming. First class training. Can't vouch for management as haven't had any dealings there yet.
Weather - It rains, sure, but there is no such thing as bad weather, just the wrong clothing. Been lovely here in the West the last week too.
Compared to the Middle East - There is no comparison. It's apples and oranges. It all comes down to lifestyle choice...ie do you want a lifestyle or money? Of the 5 expats in Shannon, 4 are ex-Middle East, that must count for something?