Plan B vs. Generic?

I know this is in the wrong room but I'm active in CC and know the ladies here and want to get decent advice as opposed to some of the riffraff in the sex rooms. 
My SO and I were just having sex and he came only a little bit but held himself off because he wanted to keep going. The condom broke but nt at the tip. We're still getting Plan B but I couldn't particularly a find good Google answer as to whether or not a generic and cheaper version would be just as effective. 
Any input would be great.