I'm not touching GDP with a ten foot pole, but I will go into standards of living.
I hesitate to qualify nations under our OTL "First World, etc" statuses, but there are definitely distinct differences for the individual in terms of quality of living. In wealthier places right now you could safely qualify standards of living roughly as those of 1950s USA, in terms of the middle class anyways. If I were pressed to say the best place to live, I'd actually go for Switzerland. It's quiet, access to cheap luxury goods from Germany, the Confederate successors, and Italy, while not being too overcrowded. It has good roads, public transportation, and good healthcare. Whether poor, rich, or in the middle, I'd say Switzerland is probably the best place to live for the largest percentage of its population.
Otherwise, what we could loosely term as a First World sort of environment (though not to same degree of disparity as OTL) would be the South America economic bloc, which despite recent tensions is still highly productive and linked. This would be Argentina, Paraguay, Uruguay, and Brazil. Admittedly, Uruguay did put a bit of a hiccup in the system, but it seems that the resolution of the crisis could very well set things straight in a hurry. Also I'd clump an assortment of other nations, but not in any one geographical location. Britain and assorted dominions (minus Guangxi) are fairly nice. Portugal is VERY nice these days in terms of available luxuries and standard of living. Vinland of course is a delightful place to live, assuming that you're not on the border with the USA.
I hesitate to qualify Germany and Italy in these estimates, as they don't have the same degree of wild consumerism and luxuries available to them as SouAmerica regions do. I'd place them in a "Second World" sort of status, along with the other South Americans not mentioned above, Aztlan, and Japan.
Of course the absolute worst place to live is probably any Subsaharan African nation. Haraldsholm itself is actually fairly nice in that portion of the continent, but everything else languishes in squalor and poverty. South Africa would be the sole exception for the moment, as it actually has functioning sewage systems and modern healthcare. Being a peasant in Russia would probably also come pretty close in a lacking lifestyle. To be fair though, it'd probably be worse to be one of the displaced serf types living in the cities, with vicious work hours, hardly any pay, and a cramped apartment, assuming they aren't living out of an alley. On the other hand, if you're rich or a member of the middle class in Russia, you can probably enjoy a very luxurious lifestyle.