Is a modded 360 really worth it?

[DOATS1]

my friend has a modded 360. he plays halo 3 on a dvd-r, and he uses xbox live. i don't know how, but he does. i went to his house because i thought he was lying, but he wasn't and i saw him put in the recodable dvd and halo 3 came up, then he actually played an online match.