Well, I have no idea if you appreciate this kind of music, but as the group has just started a little US tour you might perhaps want to check them out and try to catch them live if you find you like them.
They are two sisters from a suburb of Stockholm, Sweden, who started their career at the tender ages of 14 and 17, respectively, on Youtube with a Fleet Foxes cover. In the four years since then they have published one EP and two albums, the first one being purely acoustic and the second one with a much fuller band sound. The latter album, titled "The Lion's Roar", has been recorded and produced by Mike Mogis (from the group Bright Eyes) in Omaha, Nebraska. It has reached #1 on the Swedish charts.
Broadly spoken, their music can be classified as indie folk pop with a more or less prominent splash of country. But please don't let this stop you from checking them out even if you usually dislike country music. In addition to self-written songs they have also performed a range of covers some of which - to my ears - beat the original. The girls are excellent vocalists, and their voices, if sung alone or in amazing harmony, have become the trademark of the group.
I hope you'll enjoy FAK as much as I do. It goes without saying that reasons to love their music are quite different from reasons to love Vienna's.