TNT--I've been building bathrooms for quite a while---In my opinion it's a risky and expensive product.
When other proven methods and dependable products are available why would you suggest someone try that ?
We are entitled to our opinions---mine are based on experience---but they are just my opinion---
Take a step back and read all of my posts. I agree that the product is not the greatest and am not advocating it's use. I have stated that after a few installation I was not pleased with the slope and drainage. But you have no experience with this product, so it's not based on experience. I have seen no evidence that there are issues with movement if the mortar bed is properly installed.
Here's what I take issue with. You are using a DIY thread versus a fellow contractor's actual experience. And in that thread there is nothing outlined as a product failure. It only describes improperly installed mortar beds and a bunch of yahoo's screwing through the pan bottom to secure it.
So yes, you are entitled to your own opinion, but not your own facts. The fact is there is no evidence of a product failure in that thread.
As to trying new things when the old works, I can think of many reasons. 1) Effeciency 2) Time 3) Money 4) Better method...shall I continue? I guess that you then still install green board in showers with mastic. I mean that's the way it was done for years and worked. You cannot be using any type of waterproofing or membrane system, when the old system worked just fine as long as it was properly installed.