Hi Tallpaul,
I was talking about long term! For short term €5 is very good but there is no reduction for longer periods, even aer rianta (DAA?) do this. I e-mailed their site asking about a long term rate and they replied €5 per day. For two weeks this is €70. A bit better than DAA but not much.
It's no skin of my nose there are alternatives but with kids etc. bus can be awkward so maybe taxi for the big hols but what about all those coming from meath, kildare and further afield.
In the end of the day I don't agree that two providers signify much competition look at the banks and mobile phones for other examples of this. The planning and other restrictions around the airport make the dominace of DAA complete.