Works well for me – nice to know I have an 'automatic backup' of everything I enter into Xero "just in case". Especially as Xero is a bit of a "zero" when it comes to a simple one-click backup process (i.e. you cannot do that). Boxkite works well and automatically puts files and CSVs into my Dropbox. Recommended.
So handy to have all my invoices sitting in my Dropbox ready and waiting without having to lift a finger!