Yes, I have metadata management set to manual. I was only going to add the e-books I purchase on my Sony to the Calibre library to keep track of all the books I have so I will stop buying duplicate copies
...but was not planning on using Calibre to resend these e-books back to my device. Therefore, I set the metadata management to manual so that I won't automatically screw something up
The e-books I have added from my device to the Calibre Library appear w/o covers, reviews, etc so I use edit metadata to add this extra information on each e-book...to my knowledge it does not change the title or author since I use this information to find the metadata.
I was thinking of creating a new Library to seperate my e-books from my paperbacks, but that would defeat the purpose of having them all in one location for ease of identification and organization.