Hi, JazzMind!
Glad to meet you!

I have tried Briss and this is my report:

The program (just an executable file) will scan the PDF you choose and detect patterns of text boxes. After this is done, you have to act on the pages displayed with those patterns.

You just drag and draw boxes including the areas you want to keep. If you have a wide pdf with two columns you will draw two boxes encompassing each column. Proceed in reading order. The boxes will be numbered. The second box you draw will be defaulted at the same size of the previous one. If you misdraw a box, right click in your mouse while selecting the box and it will disappear, so you can draw again.

After you create the cropping boxes, you have a preview option, and the file is opened in Acrobat or Adobe Reader for you to see if you want to remove pages, or if you need to redo the whole thing again. You can save the PDF from Acrobat or go back to the Bliss interface and choose "Crop" to finalize, and then save.

It is very simple and fast (compared with doing this manually in Photoshop! Augh!)

Limitations: If your document has an irregular layout, things will get complicated.

All in all, it works quite well. After cropping, OCR recognition in Adobe, from there to Calibre, tagging, converting to EPUB, and to the EE.

And your inner voice: "After all the trouble, you'd better read it now!"

Thanks for the information and see you around!