copper shower pan vs rubber membrane to dry in shower pans???

I always want to give my customers and blog followers  the best advice on the most economical yet highest quality tile related installations. Ive learned this information from years of hands on  doing of the jobs myself.As you may know from my actual web site I do all my jobs personally and have over 34 years of experience. In all those years out on the job I have pretty much seen it all. So when I make a recomendation on whats the best way to go , its because Ive weighed out the best options for my customers out there on the job. I also do repairs and always have, many in my industry overlook the repairs as not being lucrative enough to warrant their time, So I do get allot of repairs.
  The most costly repair Is the leaky walk in shower pan,Which can sometimes be in excess of $500.
Ive done well over 100 of these in my career and only 1 or 2 % of these were rubber membrane repairs
and the other 98% were copper pans. In the instances of the rubber membrane repairs It was always  Improper installation by nails being nailed below the waterline.As we have all heard from the ecocriers
It takes  hundreds of years for plastic and heavy rubber products to deteriorate in the enviorment,so it only makes sense that a rubber membrane would almost never be effected by water and would  surely last past my lifetime when installed correctly.
  The Copper pan on the other hand is metal and starts the deterioration process almost immediately when in contact with water.We've all seen a green copper Penny and that green on the copper is just like rust on Iron and steel. I have removed so many copper pans that were rusted through(for lack of a better word).
Ive seen it again and again tearing out a shower floor and 12 inches up the wall because water was dripping into their living room ruining their ceiling and requiring more costly repairs.
  Further more the copper pans are very costly most have to be custom made and the plumbing labor is very expensive. The cost is $400 to $800 and even more depending on the layout of the shower floor to be dried in.
On the other hand I install rubber membrane to dry in the shower floor at a total cost of $175 and that includes the concrete in the floor to slope to the drain. I have several contractors  who  used to use copper  who now call me to come out just to dry in showers for them At a huge savings for a much more reliable and longer lasting product. Using logic and common sense  it seems obvious that for less less $$ and a longer lasting dependable shower floor the membrane Is the best call.
I dont supply materials on any of my jobs and dont never gain montaily on any of my recomendations I speak only from experience and the desire for my customers to get the most for thier money