Pricing aside, I'm quite impressed by the service so far. No proprietary programs or clumsy web apps required: just use standard tools and protocols (rsync, WebDAV, SFTP, subversion) to transfer files or mount as a filesystem. Of course, the weak link is me being too lazy to set up a cron job to automate backups, but I will get to it RSN; just need to reorganise files to make it easy to create a list of things to archive.
I'm also impressed by their philosophy. Aside from using standard protocols, they're concerned about government fishing expeditions that impact customer privacy. Non-US servers are coming for those using the geo-redundant service, and tutorials on encypting an rsync.net filesystem are also on the way.