Share your experience!
to backup your pictures, videos and/or music just transfer them to your PC or use Box.com, Google Drive, G+, etc
as for the rest
Alternatives on How to backup Xperias
The media files should be copied yourself,do not rely on an app for backing them up.For the contacts,messages,etc use pc companion,it is ok.Or myphone explorer.
In contact app is one very interesting option, "export" :smileysmileywink: This saves all contacts to one .vcf file, or each contact to separate file.
For import such files serves another option, "import" :smileysmileywink: