In my opinion, this rarer spelling looks nicer than "Austin", but is still a painfully modern-sounding name reminiscent of little boys born sometime after 2000.
This is an ugly name. The E makes me want to pronounce it differently. And it sounds bad enough on a boy, but imagine this on a girl: it's because of so many women's Jane Austen obsessions that would make them want to use it on a girl. After all, Bronte has been used on girls. What's next - Alcott? Dickinson?
This spelling makes me think of the well-known Austen Riggs psychiatric hospital in Stockbridge, Massachusetts, where I once did some temp work. Other than that regional association, I don't like this spelling of an already overly popular name.