I just purchased an Epson ES-300W.
Here is why:
I got tired of driving home to do scan backs after an appt when I could have taken another appt.
This unit has an internal battery and internal wifi to connect to the android or iOS Epson smartphone app.
It is very small and folds up into a box shape. When needed, I open it, power on, launch my phone app, initiate the scanner wifi and connect to my phone, scan the docs to my phone, disconnect the scanner wifi, upload or email the scanned docs, power down the scanner and off to my nest appt.
All from my car. Saves much time and the scanner is very fast in black and white mode (does color too). Has 25 page auto doc feeder.
Hope this helps.