VueScan will be able to do the job of scanning a book and at the same time convert the book into a searchable PDF, without needing an extra step.
Furthermore VueScan will allow you to use a timer to start a new scan, so you don't have to press a scan button or make a mouse click every time you scan a new page. Also VueScan will most likely scan significantly faster than other 3rd party software.
PDF capabilities have expanded significantly in the last updates of Vuescan, though they were very good to begin with.
Here you will find a review of an old version, though keep in mind this review is 12 years old and Vuescan has improved since then, because development has been consistently moving forward.https://www.donation...ex.php?topic=23658.0
When you buy, you need the professional version for OCR capabilities. Unless you want to use it only for one month, do the one time payment over the subscription model.
Possibly there may be a discount available when you do a google search. Maybe code OCT25 will still work for a 25% discount - not sure. If not, please do a search for "VueScan discount".
BTW: Correct - PDF Xchange Viewer has been replaced by Editor and the Viewer hasn't been updated for a long time. Editor is still free, though the free version may be hidden. I would use the free portable version at www.PortableApps.com