I wouldn't use UTF-16 unless having to work with a legacy system. A lot of software claiming to handle UTF-16 is broken and really only works with UCS-2. You ha

I wouldn't use UTF-16 unless having to work with a legacy system. A lot of software claiming to handle UTF-16 is broken and really only works with UCS-2. You have to worry about endianess and so on. If you develop an application for the international market you should probably go with UTF-8 as well. Maybe if you develop only for the Asian market it's a bit different. But in my experience significant amounts of text usually come in some form of data or markup format (HTML, XML, JSON, etc.) and usually those markup formats are defined in the ASCII subset. So UTF-8 still wins. Just take a random page from the Japanese Wikipedia and encode it in UTF-8 and in UTF-16. You'll see that UTF-8 almost always wins.