Why is Snapshot soooooooooooo slow?

I have installed and run Snapshot on several sites and am consistently finding it to be incredibly slow, taking over an hour and sometimes up to two hours just to create one backup.

I have previously been running BackupBuddy on these sites and found it completed the same backups in 2–5 minutes, but wanted to switch due to the licensing terms with BackupBuddy.

Snapshot runs quickly until it hits the files, and then slows down to a crawl for every site. And it's not just one file that seems to give it trouble; it barely moves for every single file. I know I can speed up the backup speed by not loading all files — I currently have everything selected — but it is the same setting that I had for BackupBuddy, and I do want to save all files.

Is there anything that can be done to speed this up?