I think it would be nice to have the file name displayed in the preview panel, instead of the randomly generated tag.
This way, when people are saving PDFs and other collateral, it's already named and they know what it is. I find that it could be confusing, if downloading several items.
We typically send out flyers and other documents with every campaign, to our distribution base.
It would also be nice to have the files come in as attachments for Gmail and other supported email providers -- similar to Vertical Response.
We currently have five accounts and overall, I'm very pleased with the response and delivery rate. As well as the streamlined drag-and-drop, which saves me a ton of time over having to code each campaign individually. Overall, I'm a satisfied customer.