Yeah, you must try them. They are nicer than all the Reeses products put together times 1000. Don't be put off by the pretzel layer either...it just blends in with the peanutty gorgeousness (doesn't give it a savoury flavour).
Cripes, i'm having a funny turn just thinking about them 
By the way, Hersheys do white and milk chocolate coated versions but they are nowhere near as good. I've yet to try the limited edition chocolate cookie and marshmallow varieties but as soon as i've finished my Slim Fast ordeal they will be next on my chocolate hit list 
