Yes, I also connect and add/delete books a lot.
My problems happened initially with me when I was playing around with an SD card.
Frankly, I got tired of the large lag time. This has now been correced because of these reasons (I believe):
I no longer use an SD card
The recent update
More ram in my computer
Anyway, since those changes, my PRS-505 works beautifully. The upgrade on the firmware is great, in my opinion. I've decided I really don't need 500-600 books on my Reader, but only about 300


.
Now I'm happy. The Reader is robust and there are a lot more alternatives on what format/file I can put on the device.
Have a good trip this weekend.
Don