What are some alternatives?
When comparing FreeNAS and Amahi Home Server, you can also consider the following products
OpenMediaVault - OpenMediaVault is the next generation network attached storage (NAS) solution based on Debian Linux.
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.
ClearOS - A very good alternative for Windows Server, for free
Univention Corporate Server - Univention Corporate Server UCS with Active Directory functions and App Center is the cost-efficient and popular successor to Microsoft's server solutions.