Today, I opened SubEthaEdit and found that I have 23 days left on the trial period. Put another way, I've been using it to write LaTeX for a week. It seems like an appropriate time to assess where I'm at.
Citations have not been satisfactorily resolved. I'd really like to have a keyboard shortcut that completes a partially typed citation. At the moment, I have the system services available in SubEthaEdit (and pretty much everywhere else, of course!), and copying and pasting from the reference list in BibDesk. It looks feasible to write an AppleScript to get a list of completions from BibDesk, which would do what I want. However, it would be necessary to select out the right bit of text preceding the insertion point, with correct handling of the cases where text is selected or not selected. It sounds very fiddly and time consuming, but not actually difficult. Since I am trying to test out as much as possible during the trial period, it seems best to leave this for now. On the bright side, it's not like I've actually lost anything that I had with TextMate, because the citation completion wasn't working right, anyway.
Pdfsync has been successful. It was surprisingly easy, although there was a need to dig into UI Scripting. The scripts could use a little refinement to be more robust, but work nicely enough as they are.
As a whole, the scripting dictionary for SubEthaEdit seems adequate. As is common for scripting dictionaries, there are oddities and omissions, but nothing show-stopping as of yet. The degree to which scripts can be made to look like toolbar items and menu items is rather impressive, actually.
So, what's left to do? The main things are to have means for typesetting from directly in SubEthaEdit, cleaning up all the auxiliary files, and comments. Cross references within the document could be more directly supported, although this is low priority: I use some personal LaTeX macros that reduce the need for such support, SubEthaEdit completes words from within the document, and showkeys makes the keys visible.
After that, I can't think of much that isn't just typing shortcuts, such as inserting environments, sectioning, and formatting. That's clearly possible with AppleScript, but time consuming to enter it all in. It doesn't seem that you can arrange the scripts into submenus, so it's undesirable to overdo this, anyway.