Well, peanut butter has been readily avaliable only in recent years, a few years ago you would only find it in import stores.
I have tried it, of course, as I must try everything

and for me it's ok but not something to die for.
I think I've only bought a few jars in my life. Pity me
As for chocolate/PB, no, I don't think there is anything like that here. Pity me even more!
You can find peanut caramel chocolates - that's a rather common combo and a very tasty one - and I think that peanut butter would have the same salty/sugary punch as peanut caramel, so I'm positive I would like it.
Still not close to
dulce de leche and chocolate, but that's plain decadent. Yummy yummy.