Hi. I'm watching the implementation of Roam like at home very closely as I had to amend more than 100 operators in 28+3 countries for the prepaid data wiki.
Now most countries are up to date and for prepaid users it's so far a success story. Only few countries are opting out. They got a derogation from their regulator: the Baltic States, Denmark, partly Finland.
The operators in more expensive countries were afraid to be overrun by the cheap plans from the East or North, but this hasn't materialized so far. Most providers apply a very rigid "FUP" in the cheaper countries.
The best thing: rates have come down considerably. Those providers using a FUP are at around €4.50/GB and even the "misuse rate" is only around €9.30/GB (variable by different local VAT taxes). These are rates we have dreamed of, but they are more or less in line with domestic rates in the more expensive countries in Europe.
It's true: some providers stopped offering roaming, some built in new hurdles, others give out only around 10% of their packages at domestic rates like in Poland (and still call it RLaH). So it's now essential to check every provider for their policy. Lycamobile is the internationally most known to (partly) disobey the new rules in a dozen countries. While they give out roaming at the same default rate like each domestic rate, they don't allow allowances to be used from their domestic bundles and packages.
I try to keep all EU/EEA countries updated in the prepaid Wiki with a focus on roaming. I guess users are still interested as long as this picture is so scattered. For instance, we still don't know much about the FUP against permanent roaming and how stringent it will be applied.
On this site I give a survey about what we have learned so far:
prepaid-data-sim-card.wikia.com/wiki/European_Union
For each operator in the EU/EEA please check every country site. To most operators have been added a paragraph about roaming now.
Yesterday, I dared to give first advice what a roamer in Europe is supposed to do now in the yellow box.
And please add your experience to the comments there. And when you've found the new roaming "queen" SIM card, let me know
I have already some national offers in my mind giving out lots of allowances without restrictions to EU roaming for a new recommendation list, but to check them will take some time. Much to my surprise, they don't come from usually "cheap" countries. As I like EU/EEA roaming to be a success, I don't like to give advice how to bypass rules at the moment. When the new regulations have been established and proven to be working, it may be different later. Then we may add a new list of recommended SIM cards for EU roaming again.