I've used and recommended this plugin a ton, and has mostly been a big help.
But I like others have stumbled upon a buggy update, and this is literally the worst thing that a plugin can do to a WordPress site. It's data that is not unrecoverable thanks to revisions, but this is still totally unacceptable to destroy data.
1) Switching between languages erases data
2) Update erases data
Look at this screencast (.mov only, sorry)
Version 2.5.28 on WordPress 3.3.1.