I did a two year MA in Budapest. It's hard to say whether it helps significantly for PhD apps in the US, but if you already have an MA, you are able to apply to PhD programs in the UK and continental Europe. Of course, there are other benefits too, like networking, research experience, international experience, etc. that will help you on any application. I think it all depends on your goals, your research, and your funds. For me, I was switching fields, so I felt that it was important to do a master's before applying for PhD programs, and between a great scholarship and low cost of living, it just made sense to go to school over in Europe.