I don't know all the technical reasons to do this or not to, but I have to do it with 110V and I'm going the EVGA 1600W P2 route. I haven't seen anyone here in Japan having issues running that, and I always go off of real world experiences/advice from friends/family I know are qualified vs. advice off the internet...and I would advise you to do the same! 
Which means, take everything you are reading in this post with 100 grains of salt. 
We don't have the option for 220V here. My rooms are each setup on 20A fuses and that room in particular has very low draw coming from it as it only has 2 lights and we never have them turned on. I will of course have my trusty friend over to test the pull, go over all the numbers before I hook anything up, and he will be there with me during initial power on to watch everything. If HE says there is a risk of fire or other issues, I'll think about running 2 separate 110V PSU's, but that's unlikely based on what my friend is telling me at this point. I'm not in the US though, so hard to say.
And yes, for me, it's very much worth the $400 price point to get the EVGA as that seems to be the best option at this point. Just my $0.02, YMMV!
Which means, take everything you are reading in this post with 100 grains of salt. We don't have the option for 220V here. My rooms are each setup on 20A fuses and that room in particular has very low draw coming from it as it only has 2 lights and we never have them turned on. I will of course have my trusty friend over to test the pull, go over all the numbers before I hook anything up, and he will be there with me during initial power on to watch everything. If HE says there is a risk of fire or other issues, I'll think about running 2 separate 110V PSU's, but that's unlikely based on what my friend is telling me at this point. I'm not in the US though, so hard to say. And yes, for me, it's very much worth the $400 price point to get the EVGA as that seems to be the best option at this point. Just my $0.02, YMMV!