What are some alternatives?
When comparing Amahi Home Server and NAS4Free, you can also consider the following products
OpenMediaVault - OpenMediaVault is the next generation network attached storage (NAS) solution based on Debian Linux.
FreeNAS - FreeNAS is a storage operating system strong and robust enough to meet the needs of enterprise level businesses.
Rockstor - Rockstor is a free and open source NAS (Network Attached Storage) operating system.
Zentyal - Linux directory, domain, mail, gateway and infrastructure server for SMBs.
unRAID Server - A scalable, consumer-oriented, server operating system.
SnapRAID - A backup program for disk arrays. It stores parity information of your data and it recovers from up to six disk failures.