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Pro Very flexible
An extensive feature set makes it easy to adapt to your work flow.
Pro Can store any file type
File types containing text are indexed.
Pro Full text search
Pro Completely offline
Pro Paperless office functions available in PRO Office version
Includes processing of scanned documents, OCR etc.
Con Non free/libre (proprietary)
Con Very limited automation
While the marketing claims are about an intelligent document manager, it actually does not offer many automation features, such as automatic classification, tagging and renaming of the files. It's much more like an extended file explorer...
Con Stores in a proprietary format
It stores the whole database in a proprietary file package, that you cannot easily access from another app or from the Finder. Considering you might be classifying a huge quantity of files there, it is quite problematic if you want to interact with this data from other applications.
Con Costs US$79.95 for just the Personal version
DEVONthink has not seen any major update in the last 5 years at least. Its interface still ressembles PowerPC era Mac OS X and it has not kept up with the evolution of other apps and services that could interact well with it. Most of its functionalities (e.g., OCR engine) are not at the level of current technology.