Ubuntu for the Mrs

Three days in, and MrsB's laptop is still running Linux (specifically, Ubuntu).  No complaints (yet) and none of the frustration or annoyance generated by Vista (yet?). 
A complete success then?  It's a little too early to tell, but so far, things are going well.  MrsB can do the things she wants to do; email with Thunderbird, surfing the interweb (although that's 75% Facebunk), iPlayer, etc.
How will I know when Ubuntu is truly accepted?  When I'm told I can format the 'old' hard disk containing the Vista install.
Watch this space.