The real advantage to being an EU citizen is one of the main tenets of the EU is free movement of labor. This means that you, as an EU citizen, do NOT have to file paperwork ahead of time, do NOT have to pay fees to file the paperwork and YOU, as compared to an American, can breeze through that EU citizens line at the airport (well, depending on when you arrive and how many other planes have arrived) and you can even tell the guy at the passport control that you're there looking for work and they can't put you on a plane back to where you came from. (Well, maybe they could, but it would be for more serious reasons, like your name ends with bin Ladan).
Having lived previously in the UK and having lived in Sweden now since 2000, I can say that the quality of life in Sweden is superb, truly it is, BUT from my perspective at least, that is only if you're older and have some financial security. You can't beat the nature here and personally, I don't think you can beat the medical care and support network and when I get really old, if I have to be put in a home, I hope I will come back here. But this is also a country where a large percentage of Swedes, never mind immigrants, have had problems finding work if they become unemployed and are over the age of 45. My Swedish husband, 6 points away from his doctorate, highly qualified, multi-lingual, has been unemployed for 5 years now, and it boils down to he's "too old". We're not ready to move yet (for financial and canine reasons, among others), but he gets probably 5-6 serious inquiries per month from employers in the UK, wanting to hear from him when he gets over there. Based on my C.V., I too have had London employers wanting me to get my butt over there. So financially, the future looks better for us in the UK, at least until retirement.