Thanks for the feedback.
I have been using both together for a few months now (sessions open at same time and working on common multiple projects).
I feel that VSCode offers a cleaner UI as an IDE whereas Atom is more open to extensions (“hackability”) such as adding custom tool bar items.
Currently I am working on a python script to export Atom project-viewer settings into VSCode Project Manager.
This will allow both applications to remain in sync.
I have read that even key bindings can be synced but I have not gone that far yet.
I wrote up here my first experiments in “driving” VSCode window from Atom and this works quite well using automation scripts.
The problem is finding an automation scripting tool which works across Windows/Linux/Mac. Right now I am focussed on Ubuntu workflow.
I found that VSCode offers better support for haXe development. The VSCode extensions are curated by Microsoft (which goes against the grain for Linux users). But on the other hand perhaps Atom packages are too open for anyone to write custom packages and some packages are abandoned.
I have docked both application windows in different virtual workspaces on desktop for easy toggling.
I will just add that I have installed PowerShell on Ubuntu to try to get consistency across applications (VSCode is strong in use of PowerShell).
In summary these two work horses work very well together without conflict.