I've done some simple setups and ran some simple tests so far.
The App installs fine on Bluestacks it also will control the Sonoff turning it on and off.
However you can't install a new device using BlueStacks
If you install with a phone the next time you open the app in Bluestacks it will appear.
You can delete a Sonoff from Bluestacks ,so far it appears only installing fails on Bluestacks.
There was a new update for the app so I installed it on the Bluestacks machine as well this still won't allow a device install.
However is a little cleaner looking
The app still needs some work with initial setup but basic functions are there.
You can setup the device so it turns the device connected to it on power up or remains off with power up which is nice.
It has a timer which can be set for just once or any or every day of the week.