I found myself facing the same dilema. I liked the PLB Nutrition. If I follow the specs correctly, the Nutrion and the Nature use the same recipe with the exception of the order. The nutrition simply puts the medium on top for a more firm support.
So PLB or Sleepez was the question that I was faced with. The PLB queen set was $1500 which is an outstanding price. The clincher was my fear of failure down the road. The SleepEZ allows easy open and layer replacement and that is what did it for me. Did I need the 13000? Probably not. Would the 10000 have sufficed? Probably. I wanted the additional height so that we were back up to where we were several sets ago.
See my SleepEZ 13000 Review for my further thoughts on the process.