apex vs sting king?

Is there any difference between these two lures?  They seem to be pretty much the same thing, though the bend is different.  Sting kings are a bit cheaper and have that e-chip thing though.  Do they work at different speeds or what?

My wal-mart is sold out of WM apex, but they have the WM sting kings.  Guess I could try somewhere else but I'm lazy.  

Sting king claims their lures are made to troll at a slower speed than apex', though apex claims it has a 'slow troll' bend in them, whatever that means.  Guess I'll have to try both and see.

I use WM sting Kings- and seem to do perfectly fine. In fact, that's my go-to lure for salmon, except early season, when you can't beat a purple flashy one...