Slight difference between being able to download files and having a torrent client built into a browser that associates itself by default with .torrent files (even if you already had a torrent client) without telling you.
I wouldn't mind so much if they said "Hey, did you know Opera can also download torrents? Would you like us to be the default torrent client on your PC?" and gave me the option to say no. But they don't.
To make matters worse, they become the default client for all user accounts and when you remove Opera it doesn't restore the associations you had previously, meaning you have to dick about in the Windows Registry to get it all removed.
It's obvious what they're doing is banking on the less technically adept installing it and then becoming stuck with Opera because they don't know how to undo the changes it makes to the system.
EDITED: 2 Aug 2013 19:21 by MATT