i can talk about ios ScannerPro as I use it a lot. Individual unpaid user here:
-odd but very easy to use
-produces medium or better pdf images
-after scanning saving to the cloud, print, email, text the output very easy reliable.
but the bad
-the user interface as always been backwards to logic, do the backward thingy and you will be ok
-its is consistently impossible to print some home appliance manuals for some odd reason
-focus and cropping only work if aprox 70% of the paper edge is well defined
thoughts:
-there may be free offerings for pdf scanning built into ios these days
-for house hold usage completely totally replaced a desk top scanner no problem
-i have never tried to directly save to the home file server as "smb://fileServer/pdf/new" Thinking the iPhone is no up to this tech yet.