Is DD-WRT Worth Your Time?
Too often in network troubleshooting situations, people rush into solutions before understanding their needs. Converting your router to DD-WRT (or some other third-party router firmware) has associated risk and may not provide any substantial benefit. It isn't worth your time to use DD-WRT unless you have a specific need or goal in mind. If after carefully considering your situation you conclude your router is brain damaged and want to try DD-WRT firmware, study its documentation carefully to prepare for the surgery.
→ More - DD-WRT Home Page→ See also - Upgrading Firmware on a Wireless Router


“It isn’t worth your time to use DD-WRT unless you have a specific need or goal in mind.”
This is very vague. People don’t do things unless their is a goal or need in mind: more features, more stability, learning.
With that said you should define your goal before you start and research online to ensure your intended project gives you the desired benefit.
My two cents is it is almost always worth upgrading the Linksys firmware with DDWRT v23 or v24. Linksys Routers need to be rebooted along with the modem four to five times per year while the DDWRT firmware is likely to work for well over a year before needing to be powercycled. Is that worth it? absolutely! I just bought 5 WRT54GLs for $250 on Newegg and I’ll apply DDWRT to all of them for experimental use and then use them for customers who experience problems with their routers.