I don't think it's too much of an issue, and if you do find that you want results to appear more in a different country. [Though this will lower all your other results] you can go into webmaster tools and change your country which does have a bigger impact with the rankings in the country you chose.
in my experience [my website] ranked 10 for a term.
After changing webmaster tools to my country. [My website] ranked six for that same term
I use all my servers from Canada and I appear very high in US and United Kingdom searches, so I do not see a significant issue