The Colecovision is definitely worth it if you enjoy older arcade games. Pepper II, Burgertime, Frogger, Montezuma's Revenge, Tutankham, Spy Hunter, Mouse Trap, and lots of others... they all got really solid ports on the system.
The most I've probably paid for a Colecovision game was about $30 for Mr. Do's Castle. It's cheap-ish to get games for, and a lot of them are solid old fun.