The new latex editor is now live at https://cloud.sagemath.com
* Side-by-side latex editing, with re-build on save (you can set the autosave interval if you want).
* Full forward and inverse search (using synctex)
* Nice parsing of the error log file, with buttons to jump to corresponding place in tex file and pdf file.
* Preview uses configurable-resolution png's so will work in browsers that don't have any support for pdf.
* The command to latex your document is customizable.
* The build process should run latex, bibtex, and sagetex automatically
if the log file says they need to be run; otherwise you can click a button to force a bibtex or sagetex cycle.
* Scales up to large documents -- my test document is a book! For me sitting at home working on my 134 page book, the time from making a change and clicking "save" to when it appears in the preview pane in high resolution is less than 7 seconds.
* Advantages over https://www.sharelatex.com
: free (unlimited collaborators), sagetex, forward and inverse search, higher (customizable) quality previews, if you need a full xterm for some reason (e.g., you want to manage your project with git!) you have it, scales up to large documents better, more sophisticated real-time synchronization algorithm (the others lock the editor when the network drops, or reset when it comes back -- not good), I tried to make this work on ipad/android (though you'll want to use a bluetooth keyboard).
* Disadvantages -- I've put little work into properly dealing with multi-file latex documents, error messages are not literally displayed embedded in the tex document (not sure I want this though), you must have a cloud.sagemath account (free), single file download is limited to 12MB right now.