The ability to upload large files quickly without any issues at all! They also offer free storage for up to 10GB of data as well which I love because it helps me keep my business running even if there's no money left after paying hosting fees every month or so (which happens quite often). Nothing really bad about this product but maybe some people might be disappointed with how slow their support can sometimes get when you've sent them an email multiple times asking questions they have already answered before? As far as file transfers go though, nothing comes close compared to what these guys are offering - fast delivery time AND unlimited space/bandwidth usage per account. We use Dropbox Pro primarily now for our clients' projects since we're able to transfer larger images than just 2-3MB each way via dropbox pro versus having to send emails back and forth trying different methods such as ftp etc..