I did not know there was a "great" debate between Textmate and Vim. I would expect the camps to be rather far apart. It would be nice if the "new" version of Textmate would come out. It seems to be floundering.
That said, I am a ruby developer on OS X, and I have been using TextMate as my primary editor even though I cut my teeth on basic vi usage 15 years ago. The fact that TextMate 2 is suffering serious second-system syndrome is undoubtedly a big part of why Vim is getting so much mindshare.
TextMate is an amazing editor, and in my (limited) experience, certainly one of the few in the last 2 decades to even attempt to challenge emacs/vim on their own turf (ie. lightweight powerful editors). But ultimately I think a one-developer closed source model will never be able to create a third truly great editor.
The main factors driving me towards vim are maturity and general editing optimality.
Maturity because vim has been around and is open source, so millions of wrinkles have been ironed out: very few crashing bugs, good performance on large files, handles edge cases well and has settings for probably anything you'd ever need, etc.
Optimality because vi attempts to allow editing with the fewest number of keystrokes. Becoming fluent in vi means that for any type of text editing you can make any desired change in a near optimal number of keystrokes. It's a pretty safe bet that no one will ever come up with a more optimal editor for such a wide range of tasks. Sure IDEs have a high local maxima, but they fall off quickly as you jump to files that fall outside known semantics. TextMate gives you a middle ground for writing quick snippets and commands, but I'm starting to question the long term value of that versus the benefits of universal availability and just taking some time to find good plugins for various language-specific development.
Katz's post was the catalyst to pushing me to actually go and try it; he seemed like he was a similar mindset to me, and his success spurred me on.