Hi Brett ,
I use MidKnot and find it to be consistence but others may differ in this subject , there are a few knots which can give you good results nowaday , the key is to use mono leader which the PE line can " bite " into it and for added security , I burn the end of the mono so if the knot slip , the rough edge of the burn will prevent it from slipping further . If nobody smoke ( I don't ) , just squeeze the end of the mono using plier to make it flat , this works too in preventing slippage .
Make sure when you tighten the knot to pull the PE at an angle to ensure the PE line to " bite " into the mono leader , wetting the PE line helps to lay the PE criss cross onto the mono leader better and prevent the PE line bunching on top of the other thus preventing it to " bite " onto the mono leader .
Jon .