For me personally, I do not think the game is worth $15. Lead and Gold is just not something that I would typically play, so it was nice getting it as part of Plus. I will probably continue to play a few online matches here and there ... maybe once I actually get better with the controls, I will enjoy the game more. Right now it is a fun diversion for a quick 15 min gaming session.
BTW, if you are experiencing any problems with the game freezing your PS3 (it has happened to me several times), this is a known issue, and apparently the developers are releasing a patch to address the problem.