The IRIScan Desk 7 Business is a good all-round device for fast scanning + OCR + book/document scanning, with the included software.
But if your focus is on open source, automation, free software and maximum control, then a classic scanner or a solution specifically advertised with OSS support may be better.
I always try to keep the sides of the pages as flat as possible with my fingers. This works well because the fingers are automatically hidden. I'm happy with the device as I often have to scan sheet music that is slightly larger than A4. This is the quickest and easiest way to do this, everything is always on it, you don't have to "circle" like with a flatbed scanner.