I have the occasional need to scan and/or convert scanned images into PDF format. OS X Mountain Lion does this natively, but as far as I can tell it's just an image wrapped in a PDF, so text selection, search, and signing the document isn't possible.
I've tried out the latest free trial of Adobe Acrobat Pro, which has scan to PDF functionality that does precisely what I want. Combined with its ClearScan option I've managed to get pretty decent looking PDFs at a reasonable size that I can search, select text from, and digitally sign. Awesome! Except it costs $199, which is a little steep for very occasional use.
That being said, is there anything else out there that has similar functionality at a lower price point? I'm not expecting free.
One app that keeps coming up in my search is PDFScanner, which makes the resulting PDF searchable by running it through OCR, but from what I can tell it's the equivalent of Adobe's searchable image format. One important requirement is being able to digitally sign the resulting PDF, but it's not clear if PDFScanner can do this. Text selection is nice but not absolutely necessary.