The premise of minimalist shoes (and barefoot running) is that a more natural movement style, one that should be easier in a minimalist shoe, will reduce injuries.
Anecdotal evidence (like the tens of thousands of reviews for Xero Shoes) and some simple, critical thinking (e.g. your muscles, ligaments, and tendons can outperform foam cushioning that starts to break down the moment you start using it), paints a positive picture.
Unfortunately, the companies that make truly minimalist shoes, including Xero Shoes, simply don’t have the resources to fund the long term study that could definitively answer this question.
To find out more about why researchers think that traditional padded, motion controlled, arch support running shoes may be the CAUSE of running injuries, and why truly minimalist shoes could be better, check out these resources (opens in a new tab):