When comparing ShiftEdit vs Google VM Instance, the Slant community recommends ShiftEdit for most people. In the question“What are the best cloud IDEs?” ShiftEdit is ranked 6th while Google VM Instance is ranked 13th.
Ranked in these QuestionsQuestion Ranking
Pro Low cost, high quality
Pro Revision control
Pro Syntax checking
Highlights syntax errors and automatically fix some errors
Pro Supports multiple file access points
Access files from FTP, SFTP, WebDAV, Dropbox, Google Drive or Amazon S3
Pro Supports autocomplete
Code completion for HTML tags, CSS and PHP code assist
Pro SSH support
Allows connecting directly to a server and run commands on that server.
Pro Good Customer Support
Help requests get answered quickly and successfully.
Pro Total environment control
Pro Can run any sort of web-based editor software
For example, one can run Jupyter Notebook on the VM.
Pro Real vi or Emacs editor
Pro Real Linux console
Con Non free/libre (proprietary)
Con Not user friendly
Con This is not a "cloud IDE," this is a remotely accessible virtual machine.
This topic is about the best cloud IDEs and having a Google VM Instance on the list is a bit of a stretch. That's not to say that the service isn't valuable or great, but it is a completely separate purpose. Granted, you can certainly install the necessary tools on your virtual machine to make it an IDE that is remotely accessible, but that's not exactly the ideal situation and not what someone looking for a cloud IDE is likely looking to do.
Con Can be expensive
If one selects a powerful type of instance or if one does not take care and remember to shut off the instance when it is not being used.
Con Less ideal if you have a slow internet connection
Though this applies to any Cloud IDE, as well.
Con Less ideal if you are mouse dependent
Assuming you are using Vi or Emacs, and not Jupyter or some other web-based editor that is running on the remote VM instance.