What are some alternatives?
When comparing DD-WRT and Gargoyle, you can also consider the following products
OpenWrt - OpenWrt is an open-source firmware based on Linux for wireless routers
MikroTik RouterOS - The main product of MikroTik is a Linux-based operating system known as MikroTik RouterOS.
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
LibreMesh - An Open Source Sofware for Geek-free Mesh Community Networks.
ClearOS - A very good alternative for Windows Server, for free
AdvancedTomato - A Tomato by Shibby fork with intuitive and modern flat design GUI.