Coincidentally, I posted about my first experience with 1DollarScan just a few days ago. Check out my review here: http://thomaspark.me/2012/12/digitiz...heap-and-easy/
If you send the books by USPS as "media mail", it will cut down on shipping cost.
The regular resolution is more than enough for my needs.
They provide a download link, so you don't have to worry about large email attachments. They send you emails when the book is received and then when it's ready for download.
I'd be happy to answer any other questions.