I have been anxious to better understand SharePoint 2013 / Office 365 preview and the new drag and drop. I've learned a few things in the process. I'm a fan of the drag and drop… love seeing that you can drag and drop on Surface, Mac, Chrome, Safari, Firefox and even drag between folders and libraries. I hope we can keep up the sharing…

1. You can upload only 100 documents at a time using drag and drop. Dragging 101 will give you an error "Exceeded the limit of number of files." I haven't seen a place to configure this limit.
2. You can now upload more than 50MB or even 100MB at a time. I uploaded 100 files totaling 1.3 GB at once! Amazing speed I was able to upload the files in less than 10 minutes. This is despite the maximum upload file size of 100MB in Office365.
3. The Drag and drop interface will often simply hang with large multi file upload. Tip: If you open another browser or tab to the same library you can see the files that have been uploaded and often notice that the files have already been uploaded even though the interface is still hung on the other window.
4. You can't share multiple documents at once. In Office 365 you can share a single document by putting in a full email address, a partial email address of an external user often won't resolve, but once the domain name is complete it will show it as possible to be added. Essentially it looks like it won't work until the email address is complete.
5. Search is FAST! Uploading the files I was able to use the new in list search within a couple of minutes. As well, while it may appear that the search on the list is title only, it definitely is allowing you to search within the document.