Yes these two are just two of many shower membranes. They all work. Redgard is great and always has been.

You never heard of either until two months ago. If you research a lot on the internet, you might find out about a number of products. Some are written about with fulsome praise in tones of awe. Some are just used by guys in the industry who don't spend time writing things on web sites.

If you web search a lot you you might ask why you are can read so much about Kerdi and see it praised or respected everywhere on the web. I'll guess, based on my observations. The company behind this orange sheet membrane and another one too, is good at guerilla marketing which means getting it into the hands of professionals and getting it to be "respected" too. A massive amount of marketing pressure is made to get the orange membrane to be talked about highly. There are many ways of creating buzz and pressure to make it appear to be the best thing to use. They give free courses, and free material. It is given away behind the scenes as free product to the oldtimers at one famous and friendly tilesetting advice forum, but only if the oldtimers behave just right. Then, there are many ways to make you the firsttime public fear "trying" any other way. Misinformation is one way. So the more you read the more it can appear that Kerdi is the one and only thing. The alternatives (liquid-applied membranes and foam boards faced with fiberglas mesh and gray concrete) are real amateurs in terms of modern guerilla warfare. Kerdi is successfully marketed; so successful that it seems to be a standard when actually it is the experimental product that hasn't even gotten to the stage of being permitted in certain places. So, I hope this helps in understanding that everyone will always write about Kerdi with tones of awe in their writings, except for someone like me. I got tons of free product already, from sources linked to the guerilla marketing channels. What I really wanted was clear information. What really wanted was for them not to spread misinformation, fear and doubt about the other alternatives. That is what I respect most. A little less bribing and A little more restraint and honesty.

Redgard is good. It always has been. Where you live, it is the best thing to use because the installers probably already know whatever they need to know, to use it to install a shower membrane properly. Learning another method is just a lot of effort for no gain. Redgard works. The other one works too.

To be thorough, read Redgard's instructions, call the manufacturer's technical support people, and post again if you have questions.

hope this helps