I have played with almost all models of predator cues.
5k and blak are not same the joint of black has a black phenolic insert same as p2 and 5k is solid stainless steel,also blak has different kind of weight bolt, same as used by mezz cues,i guess blak series is made by mezz cues as they are quiet identical to Predator Le11.
For P3 i see only one drawback which is , if u are use to grip the cue at extreme end of the buttcap than u would feel the cold from the steel in your hand,so u would keep it rotating in ur hand,sometimes cold sometimes not.If u grip the cue at the handle than this cue is great.One more thing about p3 is, it has a slightly fatter butt than other predator cues.For me the cue was lill too fancy and shiny.
Out of choices provided if u are ok with looks than p2 is the best bet for the money and if budget is no problem than blak,playbilty is 99% similar.