I'm also Vim user who has considered jumping to Sublime several times, but never quite managed to achieve escape velocity. (Though I hadn't realised until now that the Vintage package is an open repository)
While a couple of things are missing, mostly it's that things don't work properly.
Some random things off the top of my head:
* No block cursor (the block cursor plugin doesn't really work)
* When you switch between files, it keeps jumping back to insert mode, but you don't immediately notice (especially since there is no block cursor). There's a setting, but I've never been able to make it work.
* Autocomplete and the dot command don't work together
* Macros are flakey
* Visual mode and the dot command don't work well together
While I agree that vintage lacks some refinement, the source for the plugin is sitting in your sublime directory and is fairly easy to hack on. Things like the one-off cursors are fairly easy to fix. I'm not sure what you mean about switching files; I don't notice that particular problem. Do you have '"vintage_start_in_command_mode": true' set in your config?
As far as a vim-style editing plugin goes, vintage has by far been the best I've encountered. It's one of the few where it's fairly straightforward to add in the hacky things I've done to vim and still get a similar experience.
The code is quite nice indeed, and oh so small for a vim emulator - I've contributed a significant chunk to XVim which is positively massive in comparison, so I have some frame of reference.
The problem is that if you want all the fixes you pretty much have to compile a version with all the pull requests yourself as they don't get merged into mainline in a timely fashion. I would personally be much more keen to fix these things if I knew that my efforts along with everyone else's were expediently dealt with.
I do have vintage_start_in_command_mode set, but that apparently only works on startup (I read somewhere on the forums that it's a per-file setting, whatever that means).
Vintage is pretty good, but I don't agree that it is top shelf - ViEmu and jVi are both better Vim emulators IMO, and Vrapper and XVim are better in at least some regards.
For me it's the flexibility of window splits. In Vim I use both vertical and horizontal splits constantly, sometimes having 6 open at a time to deal with, for example, a Rails model, controller and view along with a CSS and JavaScript file and associated tests. Sublime has some window splitting but compared to Vim (or Emacs) it is pretty weak. If that is ever changed I'd consider switching.
I'm also Vim user who has considered jumping to Sublime several times, but never quite managed to achieve escape velocity. (Though I hadn't realised until now that the Vintage package is an open repository)