I would have purchased the 505 if I had found them in stock anywhere. I have the 650 instead and the fact that it looks like multiple drives on my computer just leaves me confused. Luckily, that doesn't confuse Calibre at all. It sorts my books by last name for author sort but that could be because of how I have Calibre set. I think Calibre will solve a number of the problems you have. I use the tags feature to organize my books into collections and that mostly works for me.