There are 3 main components to a normal (not peanut butter) Snickers bar, nougat, peanuts, and caramel. Sure, there's also the chocolate component, but today I'm just talking about the inside parts. Of these three inside components, Mars had to pick one to replace with peanut butter. My first choice would have probably been the caramel, my second choice, the nougat. The peanuts don't really seem like a logical choice at all since they give the only crunchy texture you get in this bar, but that's the direction Mars went.
So instead of peanuts, the Snickers Peanut Butter, gives you crushed up peanuts. It's as if I'm eating bar designed for people with false teeth, or maybe it’s designed for babies before they get their teeth. What this bar has is a layer of nougat, with a layer of peanut butter, then a layer of caramel, covered in chocolate. The biggest problem with this bar is its complete lack of crunchy texture. I think this bar is best described as a super soft mess of ingredients.
The peanut butter, caramel and nougat flavour also lack a little in the flavour category as well. The nougat is lost, the caramel is almost lost, and the peanut butter, while being the strongest flavour, doesn't hold up well compared to the chocolate.
I really think that this bar is a total disaster, except maybe in the idea that a Snickers/peanut butter combination would work. The problem is that it just doesn't work in this format.