So you're saying you trust a single developer to both write an encryption tool and run the servers it talks to more than the combined possibilities using existing open source tools to create backups by encrypting data locally and storing it remotely via ssh/sftp?
Yes, when it comes to crypto I'd put my in trust in highly talented people over trusting my own ability to glue together a collection of OSS tools anyday.
Try in 18 hours. Can you call him when something fails?
I'm not saying he isn't responsive I'm saying depending on a one-man-band who is responsible for the client software, server software and the underlying storage system (ie he is the owner of the s3 account) seems like a huge risk.
