Yep, pretty awful. After many weeks or months of waiting and praying, you will receive SOMETHING back. Sometimes I get a sense that the reviews on sites like this are overwhelmingly negative because only the pissed off customers post something; the satisfied customers never speak up. In this case, I think maybe all their customers are upset. That's why they're always on Groupon; they'd never sell their services by word of mouth otherwise.
I made the mistake of buying a second set of Groupons before receiving back my first set of slide scanning orders. I think the second set actually came back worse than the first. They were not completely out of order like my first set, but instead of vertical photos being scanned properly, they were now letterboxed left and right and cut off top and bottom - almost like they switched scanning equipment or something.
After going through the files and finding this, I spoke up. They sent me a return form and I carefully packaged everything back up for rescanning and shipped it off on my dime. Everything came back lumped together on one CD this time... with the vertical scans looking exactly the same as before. Oh, and they e-mailed me a coupon for some hypothetical time when I'd want to use their services again.