Not really. Both are excellent tools (in completely different ways).
I think the intersection of programmers who use Vim and programmers who use VS for their day job is much higher. I do a mix of .NET, Perl, Javascript, and HTML at my job, so depending on my current task, I may be using VS2010 or Vim, so it is very nice to use the same set of keybindings between applications.
It's not entirely about loving Visual Studio, it's mostly about VS being something you have to use.
Curious: why use vi inside VS and not a standalone vi or gvim?
Mainly because of the benefits VS provides, e.g. intellisense, refactoring with Resharper, macros such as Go To Declaration/Implementation, compile within the IDE and navigate to any compilation errors, run unit tests etc. etc.