Some reasonable points there - I don't know how much exactly Vodafone pays other operators. However, they appeared to go to great lengths to resist the EU roaming price cuts, and I think it is reasonable to assume they won't pay 1c less than they need to and vice versa with other operators who interconnect with them. Clearly some of the smaller operators will need to do deals to compete with the power of the big guys - so it is understandable that those alliances will spring up.

The differential between the Wholesale cost of 50MB and the 99c daily rate is such that it is hard to see this deal being economical for Vodafone in the medium term. I would say that they will revert to offering special deals if you stay on Vodafone partner networks only.

The Vodafone Ireland deal is particularly interesting because there are no restrictions on which European operators you can roam on. You can switch to any operator who has a roaming agreement with Vodafone Ireland.

I think that the deal is just a panic reaction to the Meteor Voice roaming offer, and that they have overlooked the risk that Millions of Europeans might exploit it to get free Data roaming across Europe.

I agree, Vodafone won't make a fortune at € 0.99 for 50MB and this offer is surely driven by competitive pressure. But even today Vodafone can direct their customers into their own networks through the preferred network list (so-called "PLMNsel") stored on their SIM cards (which can also be updated over the air), so upon arrival in another country the majority of customers will wind up on a Vodafone network. Of course some customers will switch to other networks once their phones get outside Vodafone's coverage and so may generate losses, but in the end this is surely cheaper than an exploding customer-churn rate in favour of Meteor.

How is Switzerland treated in these dealls? Part of Euro roaming or not?

Switzerland is included in the Vodafone Ireland free data roaming deal across Europe. The full list of countries where you can roam on this deal using a Prepaid SIM is as follows,

Austria, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, France, Germany, Greece, Hungary, Iceland, Italy, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland, UK

(Clearly Ireland is also included by default, as you won't need to roam there)

Data costs the same as in Ireland if you are in Ireland or roaming in any of these countries (0.99c per day for up to 50MB).

Thanks my question was focused on the EU partner states (e.g. those who were not members of the EU, but who had special relations, e.g. Switzerland, Iceland, Norway, etc.).